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Addition, subtraction and multiplication of fractions

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Which of the following is the reciprocal of $\dfrac{7}{9}$ ?

  1. $\dfrac {3}{7}$

  2. $\dfrac {5}{8}$

  3. $\dfrac {9}{7}$

  4. $\dfrac {6}{5}$


Correct Option: C
Explanation:

Let $\dfrac{p}{q}=\dfrac{7}{9}$


where $p=7,q=5$

$\therefore$ the reciprocal of the given fraction $\dfrac{q}{p}=\dfrac{9}{7}$

By what number should we multiply ${(-8)}^{-1}$ to obtain ${12}^{-1}$?

  1. $\dfrac{1}{4}$

  2. $\dfrac{-2}{3}$

  3. $-2$

  4. $\dfrac{-3}{2}$


Correct Option: B
Explanation:

Let the number be $n$

then, 
        ${\left( { - 8} \right)^{ - 1}} \times x = {\left( {12} \right)^{ - 1}}$

        $= \dfrac{{ - 1}}{8} \times x = \dfrac{1}{{12}}$    $\because \left[ {{{\left( {\dfrac{a}{b}} \right)}^{ - n}} = {{\left( {\dfrac{b}{a}} \right)}^n}} \right]$

       $ = x = \dfrac{1}{{12}} \times  - 8$ 

       $ = x = \dfrac{{ - 2}}{3}$

Simplify $\dfrac{2}{4} \times \dfrac{3}{7}$

  1. $\dfrac{3}{14}$

  2. $\dfrac{6}{14}$

  3. $\dfrac{3}{17}$

  4. $\dfrac{6}{17}$


Correct Option: A
Explanation:

$\cfrac{2}{4} \times \cfrac{3}{7} = \cfrac{1}{2} \times \cfrac{3}{7} = \cfrac{3}{14}$

Hence, $\cfrac{3}{14}$ is the correct answer.

A farmer has 192 animals, out of which $\dfrac{7}{16}$ are cattles. $\dfrac{2}{3}$ of cattles are dairy cows. How many dairy cows he has?

  1. $128$

  2. $84$

  3. $56$

  4. $112$


Correct Option: C
Explanation:

Total number of Animals $=192$


Total number of Cattles $=\dfrac{7}{16}\times$ No. Of Animals $=\dfrac{7}{16}\times 192 = 84$

Total number of Dairy Cows $=\dfrac{2}{3}\times$ No. Of Battles $=\dfrac{2}{3}\times 84 = 56$

$\therefore$  The farmer has $56$  dairy cows

Solve: $2 \dfrac { 1 } { 2 } \mathrm {  } \text { of } 10 \mathrm { cm }$

  1. 30 cm

  2. 25 cm

  3. 20 cm

  4. 50 cm


Correct Option: B
Explanation:

Given $2 \dfrac { 1 } { 2 } \mathrm {  } \text { of } 10 \mathrm { cm }$


$=2\dfrac{1}{2}\times 10$

$=\dfrac{2\cdot2+1}{2}\times 10$

$=\dfrac{5}{2}\times 10$

$=5\times 5=25$

Simplify the expression $2\dfrac{1}{4}\times \dfrac{5}{12}+\dfrac{1}{2}$

  1. $\dfrac{23}{16}$

  2. $5\dfrac{5}{2}$

  3. $4\dfrac{3}{3}$

  4. $3\dfrac{1}{5}$


Correct Option: A
Explanation:

$2\cfrac { 1 }{ 4 } \times \cfrac { 5 }{ 12 } +\cfrac { 1 }{ 2 } $


$=\cfrac { 9 }{ 4 } \times \cfrac { 5 }{ 12 } +\cfrac { 1 }{ 2 } $

$ =\cfrac { 15 }{ 16 } +\cfrac { 1 }{ 2 } $

$ =\cfrac { 15+8 }{ 16 } $

$ =\cfrac { 23 }{ 16 } $

Reciprocal of $2\dfrac{1}{5}+3\dfrac{2}{5}$

  1. $\dfrac{11}{17}$

  2. $\dfrac{5}{28}$

  3. $\dfrac{17}{12}$

  4. $\dfrac{12}{28}$


Correct Option: B
Explanation:
Given,

$2\dfrac{1}{5}+3\dfrac{2}{5}$

$=\dfrac{11}{5}+\dfrac{17}{5}$

$=\dfrac{28}{5}$

reciprocal is,

$=\dfrac{5}{28}$

The value of  $\displaystyle 999\frac{995}{999}\times 999$ is

  1. $990809$

  2. $998996$

  3. $999824$

  4. $998999$


Correct Option: B
Explanation:

$999\dfrac { 995 }{ 999 } \times 999=\quad 999\times 995\=\dfrac { 999\times 999+995 }{ 999 } \times 999\=998996$

So correct answer will be option B

What is the value of $\cfrac{1}{9}$ of $\cfrac{1}{6}$ of $\cfrac{1}{3}$ of  $56052 ?$

  1. $356$

  2. $336$

  3. $376$

  4. $346$


Correct Option: D
Explanation:

Given expression $\displaystyle \frac{1}{9}\times\frac{1}{6}\times\frac{1}{3}\times56052=346$

What is the product $\displaystyle \left ( 1-\frac{1}{2} \right )\left ( 1-\frac{1}{3} \right )\left ( 1-\frac{1}{4} \right )......\left ( 1-\frac{1}{n} \right )$ equal to  when simplified?

  1. $\displaystyle \frac{1}{n}$

  2. $1$

  3. $2$

  4. $0$


Correct Option: A
Explanation:

$\displaystyle \left ( 1-\frac{1}{2} \right )\left ( 1-\frac{1}{3} \right )\left ( 1-\frac{1}{4} \right )......\left ( 1-\frac{1}{n} \right )=\frac{1}{2}\times \frac{2}{3}\times \frac{3}{4}\times ......\times \frac{n-2}{n-1}\times \frac{n-1}{n}=\frac{1}{n}$

If a man spends $\displaystyle \frac{5}{6}$ th part of money and then earns $\displaystyle \frac{1}{62}$ part of the remaining money, what part of his money is with him now?

  1. $\displaystyle Rs\frac{1}{4}$

  2. $\displaystyle Rs\frac{3}{4}$

  3. $\displaystyle Rs\frac{5}{4}$

  4. $\displaystyle Rs\frac{1}{5}$


Correct Option: A
Explanation:

Let the money with the man at first be Rs 1
$\displaystyle \therefore $ Money spent=$\displaystyle \frac{5}{6}of Rs1=Rs\frac{5}{6}$
Remaining money=$\displaystyle =1-\frac{5}{6}=Rs\frac{1}{6}$
Money earned$\displaystyle =\frac{1}{2}=Rs\frac{1}{6}=Rs \frac{1}{12}$
$\displaystyle \therefore $ Total money with him now=Rs$\displaystyle \frac{1}{6}+Rs.\frac{1}{12}=Rs.\frac{3}{12}=Rs.\frac{1}{4}$
$\displaystyle \therefore \frac{1}{4}th$ part of the money is with him now

The value of $\displaystyle 15$ of $\cfrac{1}{5}$ is 

  1. $\displaystyle \frac{1}{75}$

  2. $\displaystyle \frac{151}{5}$

  3. $3$

  4. $-3$


Correct Option: C
Explanation:

$15$ of $\cfrac{1}{5}=15\times\cfrac{1}{5}=3$

Hence, option C is correct.

Reciprocal of $\displaystyle 3\frac{1}{2}$ is 

  1. $\displaystyle \frac{7}{2}$

  2. $\displaystyle \frac{2}{7}$

  3. $\displaystyle 1\frac{2}{3}$

  4. none


Correct Option: B
Explanation:

The reciprocal of a number is just divide 1 by the number.
$\therefore$ Reciprocal of $3\cfrac 12$ i.e $\cfrac 72$ is $\cfrac 27$
Option B is correct.

$\cfrac {4}{7}\times \cfrac {7}{4}\times 0=.......$

  1. $28$

  2. $1$

  3. $0$

  4. none


Correct Option: C
Explanation:

Any number multiplied with $0$ gives $0$. 

So, $\cfrac {4}{7}\times \cfrac {7}{4}\times 0=0$
Hence, correct answer is option C.

Find $x$ if $\left (\cfrac {1}{2}\times \cfrac {1}{3}\right )\times \cfrac {1}{4}= x \times \left (\cfrac {1}{3}\times \cfrac {1}{4}\right )$.

  1. 1

  2. $\dfrac {1}{5}$

  3. $\dfrac {1}{2}$

  4. $\dfrac {1}{3}$


Correct Option: C
Explanation:

The given question shows the associative property of multiplication i.e. 

$\left( a\times b \right) \times c=a\times \left( b\times c \right) $
$\left (\cfrac {1}{2}\times \cfrac {1}{3}\right )\times \cfrac {1}{4}= x \times \left (\cfrac {1}{3}\times \cfrac {1}{4}\right )$
Therefore, $x=\dfrac{1}{2}$
Hence, the correct answer is option C.

Product of $\displaystyle \frac {12}{24}$ and $\displaystyle \frac {36}{72}$ is

  1. $\displaystyle \frac {16}{24}$

  2. $\displaystyle \frac {3}{5}$

  3. $4$

  4. $\displaystyle \frac {1}{4}$


Correct Option: D
Explanation:

We need to find product of $\displaystyle \frac {12}{24}, \frac {36}{72}$


$\therefore \displaystyle \frac{12}{24} \times \frac{36}{72} = \frac{1}{2} \times \frac{1}{2} $

$=\displaystyle  \frac{1}{4}$

Reciprocal of $3\displaystyle \frac {1}{2}$ is

  1. $\displaystyle \frac {7}{2}$

  2. $\displaystyle \frac {2}{7}$

  3. $1\displaystyle \frac {2}{3}$

  4. None of these


Correct Option: B
Explanation:

$3\dfrac12=\dfrac {3\times 2+1}{2}=\dfrac72$


Hence reciprocal of $\dfrac 72=\dfrac 27$

If 0.111 is approximately equal to $\displaystyle\frac{1}{9}$ then the approximate value of 0.777 is

  1. $\displaystyle\frac{5}{9}$

  2. $\displaystyle\frac{7}{9}$

  3. $\displaystyle\frac{2}{9}$

  4. $\displaystyle\frac{1}{9}$


Correct Option: B
Explanation:

$0.0777\,=\,7\,\times\,0.111$
$=\,7\,\times\, \displaystyle\frac{1}{9}\,=\, \displaystyle\frac{7}{9}$

The product of two rational numbers $\displaystyle \frac{-9}{16}$. If one of the numbers is $\displaystyle \frac{-4}{3}$ then the other number is:

  1. $\displaystyle \frac{36}{48}$

  2. $\displaystyle \frac{25}{64}$

  3. $\displaystyle \frac{27}{49}$

  4. $\displaystyle \frac{27}{64}$


Correct Option: D
Explanation:
Let the required no. be $x$.
$\therefore x \times  {\cfrac{-4}{3} = \cfrac{-9}{16}}$
$\Rightarrow x =  {\cfrac{-9/16}{-4/3} = \cfrac{-9}{16} \times \cfrac{-3}{4} = \cfrac{27}{64}}$

The product of a rational number and its reciprocal is

  1. $0$

  2. $1$

  3. $-1$

  4. none


Correct Option: B
Explanation:

The product of rational number with its reciprocal is always equal to $1$.


Let's take an example,
Rational number $= \dfrac{2}{3}$
Its reciprocal $= \dfrac{3}{2}$

Product $= \dfrac{2\times3}{3\times2} = 1$

The reciprocal of 14 is

  1. $\displaystyle \frac { 14 }{ 1 }$

  2. $\displaystyle \frac { 1 }{ 14 }$

  3. 14

  4. 1


Correct Option: B
Explanation:
remember
whenever asked reciprocal of a number just exchange the numerator and the denominator..
hence reciprocal of 14 is 1/14..

Reciprocal of $\displaystyle \frac {7} {2} $ is-

  1. $\displaystyle 3\frac {1} {2} $

  2. $\displaystyle \frac {2} {7} $

  3. $\displaystyle \frac {7} {2} $

  4. None of these


Correct Option: B
Explanation:

reciprocal of 7/2 is 2/7..

Product of $\displaystyle \frac {10} {11} \times \frac {15} {3}\times \frac {0} {5}$ is

  1. $\displaystyle \frac {10} {33} $

  2. 0

  3. $\displaystyle \frac {150} {495} $

  4. None of these


Correct Option: B
Explanation:

zero multiplied by any number is zero..

So $\dfrac{10}{11}\times \dfrac{15}{3}\times\dfrac{0}{5}=0 $

$\displaystyle 20\times \frac {1} {4}\times .........= 0 $

  1. 5

  2. 6

  3. 0

  4. None of these


Correct Option: C
Explanation:

zero multiplied by any number is zero

Hence, $\displaystyle 20\times \frac {1} {4}\times 0= 0 $

If  $ \displaystyle \left | x \right | =\left | \frac{-3}{5} \right |  $ and  $ \displaystyle \left | y \right | =\left | \frac{4}{-7} \right |  $ find  $ \displaystyle \left | x \right | \times\left | y \right |  $ 

  1. $ \displaystyle \frac{12}{35} $

  2. 1

  3. 0

  4. $ \displaystyle \frac{35}{12} $


Correct Option: A
Explanation:

$ \displaystyle \left | x \right | =\left | \frac{-3}{5} \right |  $ and  $ \displaystyle \left | y \right | =\left | \frac{4}{-7} \right |  $ 

Since $|x|=|-x|$, therefore $|x|\times |y|=\dfrac{3}{5}\times \dfrac{4}{7}=\dfrac{12}{35}$

Product of $\dfrac {12}{24}$ and $\dfrac {36}{72}$ is

  1. $\dfrac {16}{24}$

  2. $\dfrac {3}{5}$

  3. $4$

  4. $\dfrac {1}{4}$


Correct Option: D
Explanation:

(12/24)×(36/72)

=(1/2)×(3/6)
=(1/2)×(1/2)
=1/4
So option D is the correct answer.

Multiply $1\frac {1}{3}\times 3\frac {1}{4}\times \frac {7}{8}$

  1. $3\frac {18}{24}$

  2. $2\frac {19}{24}$

  3. $3\frac {19}{24}$

  4. $2\frac {18}{24}$


Correct Option: C
Explanation:

To multiply mixed fractions we convert them into improper fractions.

In the question, 1 whole 1/3× 3 whole 1/4 ×7/8
(3×1+1)/3×(4×3+1)/4×7/8
=4/3×13/4×7/8
=2/3×13/4×7/4
=1/3×13/2×7/4
=91/24
=3 whole 19/24
So, option C is the correct answer.

The daily consumption of milk of a family is $3\dfrac {1}{4}$ litres. The quantity of milk consumed by the family during the month of June 2008 is

  1. $90$ litres

  2. $100\dfrac {1}{2}litres$

  3. $97\dfrac {1}{2} litres$

  4. none of these


Correct Option: C
Explanation:

June 2008 has 30 days.
$30\times 3\dfrac {1}{4}=30\times \dfrac {13}{4}=97\dfrac {1}{2} litres$.

Ravi had $\dfrac {5}{6}$ of a cake. He ate $\dfrac {2}{3}$ of it. What part of the cake did he eat?

  1. $\dfrac {5}{9}$

  2. $\dfrac {10}{12}$

  3. $\dfrac {10}{6}$

  4. $\dfrac {10}{3}$


Correct Option: A
Explanation:

$=\dfrac {5}{6}\times \dfrac {2}{3}=\dfrac {10}{18}=\dfrac {5}{9}$

The product of a fractional number and its multiplicative inverse is

  1. 0

  2. 1

  3. number itself

  4. none of these


Correct Option: B
Explanation:

If the product of two numbers is 1, then each number is known as multiplicative inverse or the reciprocal of one another. ... Hence, the product of a fractional number and its multiplicative inverse is 1

Veronica can type 28 words per minute. At this rate, how many words can Veronica type in $\displaystyle 5 \frac{1}{2}$ minutes ?

  1. 154

  2. 156

  3. 159

  4. 162


Correct Option: A
Explanation:

Veronica can type words in $1$ minute $=28$.


Veronica can type words in $5\dfrac{1}{2}$ minutes
$=5\dfrac{1}{2}\times 28$
$=154$

Hence, this is the answer.

Reciprocal of $\displaystyle \frac{6}{3}$ is

  1. $\displaystyle -\frac{6}{3}$

  2. $\displaystyle -\frac{3}{6}$

  3. $\displaystyle \frac{3}{6}$

  4. 36


Correct Option: C
Explanation:
We find the reciprocal of a fraction we flip it.
The definition of "reciprocal" is simple. To find the reciprocal of any number, just calculate "1 ÷ (that number)." For a fraction, the reciprocal is just a different fraction, with the numbers "flipped" upside down (inverted).
In this case, the reciprocal of 6/3 is 3/6.
So option C is the correct answer.

Indian cricket team won 4 more matches than it lost with New Zealand If it won $\displaystyle\frac{3}{5}$ of its matches how many matches did India play

  1. 8

  2. 12

  3. 16

  4. 20


Correct Option: D
Explanation:

Let the number of matches lost = x
Number of matches won = x + 4
Total matches played = x + x +4
                                   = 2x + 4
We have,
x + 4 = $\displaystyle\frac{3}{5}\left ( 2x + 4 \right )$
5x + 20 = 6x + 12
x = 8
$\displaystyle\therefore $ total matches played = 2x + 4
$\displaystyle= 2\left ( 8 \right )+ 4= 20$

The equivalent fraction of $ \displaystyle \frac{10}{11}  $ having the numerator 40 is _________

  1. $ \displaystyle \frac{40}{11} $

  2. $ \displaystyle \frac{44}{40} $

  3. $ \displaystyle \frac{40}{44} $

  4. $ \displaystyle \frac{10}{40} $


Correct Option: C
Explanation:

The equivalent to the given fraction 10/11 having the numerator 40 should have a denominator divisible by 11. The only option with a denominator divisible by 11 is option C. 44 is divisible by 11 and 40 is divisible by 10. So,

Option C is the correct answer.

The equivalent fraction of $ \displaystyle \frac{2}{3}  $ having the denominator 18 is

  1. $ \displaystyle \frac{2}{18} $

  2. $ \displaystyle \frac{18}{3} $

  3. $ \displaystyle \frac{12}{18} $

  4. $ \displaystyle \frac{18}{27} $


Correct Option: C
Explanation:

Only options A and C have denominators 18 in their options.

If we change anything in the denominator, we have to do a change of the same value in the numerator also. In option A this property is not fulfilled.
However in option C we find (2×6)/(3×6)
Option C is the equivalent fraction
2/3≈12/18
So option C is the correct answer.

$ \displaystyle \frac{1}{5}\, of\,10 km=   $ _____m

  1. 2

  2. 200

  3. 20

  4. 2000


Correct Option: D
Explanation:

$ \displaystyle \frac{1}{5}  $ of 10 km 

$ \displaystyle \frac{1}{5}\times10 \ km  $= 2 km=2000 m

If $ \displaystyle \frac{2}{5}=\frac{x}{15}$ then what is the value of x

  1. 2

  2. 3

  3. 5

  4. 6


Correct Option: D
Explanation:
$ \displaystyle \frac{2}{5}=\frac{x}{15}$
$ \displaystyle \frac{2}{5}= \frac{2}{5}\times\frac{3}{3}=\frac{6}{15}  $
$\therefore$ x is  6.

If  $ \displaystyle \frac{25}{30}= \frac{x}{6}  $ then  what is the value of x

  1. 6

  2. 4

  3. 5

  4. 3


Correct Option: C
Explanation:
$ \displaystyle \frac{25}{30}= \frac{x}{6}  $
$ \displaystyle \frac{25}{30}=\frac{25\div 5}{30\div 5}=\frac{5}{6}  $
$\therefore$ x is 5

State whether True or False.
$\dfrac{\sqrt{3}}{2}$ and $\dfrac{2\sqrt{3}}{3}$ are reciprocals.

  1. True

  2. False


Correct Option: A
Explanation:
Yes: The product of a number and its reciprocal must equal 1. 
To test whether or not two numbers are reciprocals, multiply them. 
If the product is 1, they are reciprocals; if it is not, they are not:

$\displaystyle \frac{\sqrt{3}}{2}\times \frac{2\sqrt{3}}{3}=\frac{2(\sqrt{3})^2}{2(3)} = \frac{6}{6}=1$ 

Thus, the numbers are indeed reciprocals.
GIven statement is true.

Rename the following fraction as percents.
$\cfrac { 44 }{ 400 } $

  1. $10\%$

  2. $11\%$

  3. $!2\%$

  4. $13\%$


Correct Option: B
Explanation:

When we talk about percents, we should multiply the number with $100$


So, the given fraction in percents is $\dfrac{44}{400} \times 100 = \dfrac{4400}{400} = 11$ $\%$

$\left ( \frac{\sqrt{625}}{11}\times \frac{14}{\sqrt{25}}\times \frac{11}{\sqrt{196}} \right )$ is equal to:

  1. 5

  2. 6

  3. 8

  4. 11


Correct Option: A
Explanation:

$\frac{25}{11}\times \frac{14}{5}\times \frac{11}{14}=5$.

_____ has no reciprocal

  1. $0$

  2. $1$

  3. $-1$

  4. $\dfrac {1}{4}$


Correct Option: A
Explanation:
Reciprocal of $0$ will be $\dfrac{1}{0}$ and we know that $\dfrac{1}{0}$ is not defined.
Thus, the reciprocal of $0$ is not defined
Hence, $0$ does not have a reciprocal.

Multiply the following. Write the answer as a mixed fraction.
$\cfrac { 2 }{ 9 } \times 5$  

  1. True

  2. False


Correct Option: A
Explanation:

$\dfrac{2}{9} \times 5$


Can be written as


$=\dfrac{10}{9} $

$=1\dfrac{1}{9} $

Multiply the following. Write the answer as a mixed fraction.
$\cfrac { 1 }{ 3 } \times 4$

  1. $1\cfrac{1}{3}$

  2. $\cfrac{4}{3}$

  3. $1\cfrac{2}{3}$

  4. $1\cfrac{4}{3}$


Correct Option: A
Explanation:

$\dfrac{1}{3} \times 4$

Can be written as

$=\dfrac{4}{3} $

$=1\dfrac{1}{3} $

Find the following product:
$2\cfrac { 1 }{ 3 } \times 3\cfrac { 1 }{ 5 } $

Ans$=7\dfrac{7}{15}$

  1. True

  2. False


Correct Option: A
Explanation:

$2\dfrac{1}{3}\times 3\dfrac{1}{5}$


Can be written as


$\dfrac{7}{3}\times \dfrac{16}{5}$

$=\dfrac{112}{15}$

$=7\dfrac{7}{15}$

Which pair of numbers does not have a product equal to $36$?

  1. ${ -4, -9}$

  2. ${ -3, -12}$

  3. $\left{ \displaystyle\frac{1}{2} , -72\right}$

  4. ${1, 36}$


Correct Option: C
Explanation:

Option A= Product of $-4$ and $-9$=$-4\times -9=36$

Option B=Product of $-3$ and $-12$= $-3\times -12=36$
Option C= Product of $\dfrac{1}{2}$ and $-72$=$\dfrac{1}{2}\times{-72}=-36$
Option D= Product of $1$ and $36$ = $1\times 36=36$
Option C is the correct answer.

Which of the following statements is INCORRECT?

  1. Zero has a reciprocal

  2. The product of two negative rational numbers is always positive

  3. The reciprocal of a positive rational number is always positive

  4. The product of two positive rational numbers is always positive


Correct Option: A
Explanation:

Zero can't have a reciprocal because
$1/0$ is not defined.
The rest statements are
$(-a)\times (-b)=ab$
Reciprocal of $a$ is $1/a$
$a\times b=ab$
where $a$ and $b$ are positive.

Rest all statements are true except for option A.

The value of $\left (-\dfrac {7}{2}\right )^{-1}$ is _________.

  1. $-1$

  2. $\dfrac {7}{2}$

  3. $-\dfrac {2}{7}$

  4. $\dfrac {-7}{2}$


Correct Option: C
Explanation:

To find $\left(-\dfrac{7}{2}\right)^{-1}$


Any fraction raised to negative power yields same result as of its reciprocal with modulus of the power.

$\therefore \left(-\dfrac{7}{2}\right)^{-1} = -\dfrac{2}{7}$

Which of the following statements is true?

  1. Every point on the number line represents a rational number

  2. The product of a rational number and its reciprocal to $0$

  3. $(17\times 12)^{-1}=17^{-1}\times 12$

  4. Reciprocal of $\displaystyle\frac{1}{a}$, $a$ $\neq 0$ is $a$


Correct Option: D
Explanation:

(1) Every point on the line doesn't represent a ration number, it represents the real number,  which includes both rational and irrational numbers.


(2) Let's say $a$ is a rational number,
Its reciprocal will be $\dfrac{1}{a}$
The product will be $ a \times  \dfrac{1}{a} =1$.

(3) $(17 \times  12)^{-1}$
$=$ $ \dfrac{1}{17\times 12}$
$=$ $ \dfrac{1}{17} \times  \dfrac{1}{12}$
$=$ ${17}^{-1} \times  {12}^{-1}$

(4) Reciprocal of $\dfrac{1}{a}$
$= \dfrac{1}{\dfrac{1}{a}}$
$=$ $a$
But $\dfrac{1}{a}$ is defined only if $ a \neq0$

The algebraic expression for the statement "Product of $x$ and reciprocal of $a$, subtracted from the product of $y$ and reciprocal of $b"$ is ___________.

  1. $\dfrac {y}{b} - \dfrac {x}{a}$

  2. $\dfrac {y - x}{a - b}$

  3. $xa - yb$

  4. $\dfrac {1}{yb - xa}$


Correct Option: A
Explanation:

Product of $x$ and reciprocal of $a$ $=$ $x\times \dfrac{1}{a}= \dfrac{x}{a}$
Product of $y$ and reciprocal of $b$ $=$ $y\times \dfrac{1}{b}= \dfrac{y}{b}$
Therefore, the algebraic expression is $\dfrac{y}{b}-\dfrac{x}{a}$.

Hence, option A is correct.

Find the value of x and y respectively.
5$\dfrac{1}{x}$ $\times y$ $\dfrac{3}{4}$ = 20

  1. $3, 1$

  2. $3, 3$

  3. $4, 1$

  4. $5, 3$


Correct Option: B
Explanation:

Put x = 3 and y = 3 of LHS, we get
5$\dfrac{1}{3}$ $\times$ 3$\dfrac{3}{4}$ = $\dfrac{16}{3}$ $\times$ $\dfrac{15}{4}$ = 4 $\times$ 5 = 20

If we multiply a fraction by itself, the fraction thus obtained is $\displaystyle\frac{16}{81}$. The original fraction is?

  1. $\displaystyle\frac{8}{27}$

  2. $\displaystyle 2\frac{2}{3}$

  3. $\displaystyle 2\frac{1}{3}$

  4. $\displaystyle\frac{4}{9}$


Correct Option: D
Explanation:

Let the original fraction be $\dfrac{x}{y}$.

$\Rightarrow$  According to the given question,
$\Rightarrow$  $\dfrac{x}{y}\times \dfrac{x}{y}=\dfrac{16}{81}$

$\Rightarrow$  $\left(\dfrac{x}{y}\right)^2=\dfrac{16}{81}$
$\rightarrow$  Taking square root on both sides we get,
$\Rightarrow$  $\dfrac{x}{y}=\dfrac{4}{9}$

Which of the following statements is true?

  1. 1 and -1 are reciprocal of themselves.

  2. Zero has no reciprocal.

  3. The product of the two middle rational numbers is a rational number.

  4. All of these


Correct Option: D
Explanation:

Option A

Reciprocal of a number is the number obtained by dividing it by $1$. 
Here, reciprocal of $1 = \dfrac{1}{1} = 1$ and reciprocal of $-1 = \dfrac{1}{-1} = -1$
Hence, they are both the reciprocals of themselves.

Option B
Reciprocal of $0$ can be denoted as $\dfrac{1}{0}$ which isn't defined. Anything divided by $0$ is not defined.

Option C
Addition, subtraction, multiplication or division of a rational number with another rational number always gives a rational number.

$\therefore$ All the statements are correct.

A farmer grows vegetable in his field. In $\dfrac{2}{3}$ of the field, he grows potatoes, in $\dfrac{1}{4}$ he grows onions and in the rest of the field he grows tomatoes. In what part of the field does he grow tomatoes?

  1. $\dfrac{1}{12}$

  2. $\dfrac{11}{12}$

  3. $\dfrac{3}{4}$

  4. $\dfrac{1}{6}$


Correct Option: A
Explanation:

Part of field in which potatoes are grown $= \dfrac{2}{3}$ 


Part of field in which onions are grown $= \dfrac{1}{4}$ 

$\Rightarrow$ Total part of field covered by potatoes and onions $= \dfrac{2}{3} + \dfrac{1}{4} = \dfrac{11}{12}$

$\therefore$ Remaining part of field in which tomatoes are grown $= 1 - \dfrac{11}{12} = \dfrac{1}{12}$

Which one of the following is same as $30\%$ of $40\%$ of $560$?

  1. $60\%$ of $40\%$ of $280$

  2. $15\%$ of $80\%$ of $280$

  3. $30\%$ of $40\%$ of $280$

  4. $15\%$ of $80\%$ of $140$


Correct Option: A
Explanation:

30% of 40% of 560 = $\dfrac{30}{100}\ \ \times\dfrac{40}{100}\ \ \times 560\ \ = 67.2 $



Option A: 
60% of 40% of 280 = $\dfrac{60}{100}\ \ \times\dfrac{40}{100}\ \ \times 280\ \ = 67.2 $


Option B: 
15% of 80% of 280 = $\dfrac{15}{100}\ \ \times\dfrac{80}{100}\ \ \times 280\ \ = 33.6$


Option C: 
30% of 40% of 280 = $\dfrac{30}{100}\ \ \times\dfrac{40}{100}\ \ \times 280\ \ = 33.6$


Option D: 
15% of 80% of 140 = $\dfrac{15}{100}\ \ \times\dfrac{80}{100}\ \ \times 140\ \ = 16.8$


So, 30% of 40% of 560 = 60% of 40% of 280

Option A is correct





If $\dfrac{m}{n} = \dfrac{4}{3}$ and $\dfrac{r}{t} = \dfrac{9}{14}$, the value of $\dfrac{3mr - nt}{4nt - 7mr}$ is:

  1. $-5\dfrac{1}{2}$

  2. -$ \dfrac{11}{14}$

  3. -$1 \dfrac{1}{4}$

  4. $\dfrac{11}{14}$

  5. none of these


Correct Option: B
Explanation:

$\cfrac { m }{ n } =\cfrac { 4 }{ 3 } ,\cfrac { r }{ t } =\cfrac { 9 }{ 14 } \ m=\cfrac { 4n }{ 3 } ,r=\cfrac { 9t }{ 14 } \ mr=\cfrac { 6nt }{ 7 } \ 3mr-nt=\cfrac { 18nt }{ 7 } -nt=\cfrac { 11nt }{ 7 } \ 4nt-7mr=4nt-6nt=-2nt\ \cfrac { 3mr-nt }{ 4nt-7mr } =-\cfrac { 11 }{ 14 } $

In the multiplication of $\dfrac{2}{3}$ with $4$, the numerator will be :

  1. $2$

  2. $8$

  3. $4$

  4. $12$


Correct Option: B
Explanation:

Given multiplication of $\dfrac{2}{3}$ with $4$

$\dfrac{2}{3}\times 4=\dfrac{2\times4}{3}=\dfrac{8}{3}$
The numerator of the fraction is $8$

If $\frac{2}{3}$  of $48$ is simplified, the answer is

  1. $36$

  2. $32$

  3. $30$

  4. $28$


Correct Option: B
Explanation:

$\frac{2}{3}$  of $48$
        $=\frac{2}{3}\times48$
        $=2\times16$
        $=32$

Simplify $\frac{-39}{3}\times\frac{19}{5}\times\frac{-45}{38}$

  1. $\frac{117}{2}$

  2. $\frac{-117}{2}$

  3. $\frac{127}{2}$

  4. $\frac{-127}{2}$


Correct Option: A
Explanation:

$\frac{-39}{3}\times\frac{19}{5}\times\frac{-45}{38}$
$=\frac{-13\times-9}{2}$
$=\frac{117}{2}$

Multiply $\frac{-2}{11}\times\frac{-44}{16}$

  1. $-2$

  2. $4$

  3. $\frac{1}{2}$

  4. $-4$


Correct Option: C
Explanation:

$\frac{-2}{11}\times\frac{-44}{16}$
$=\frac{-1\times-4}{8}$
$=\frac{-1\times-1}{2}=\frac{1}{2}$

If $\large{1\frac{2}{7}}$ of $\large{\frac{56}{63}}$ is simplified. Then the answer is

  1. $\large{\frac{8}{7}}$

  2. $\large{1\frac{1}{7}}$

  3. $\large{\frac{8}{5}}$

  4. $\large{1\frac{3}{5}}$


Correct Option: A,B
Explanation:

$\large{1\frac{2}{7}}$ of $\large{\frac{56}{63}}$
$=\large{\frac{9}{7}} \times \large{\frac{56}{63}}$
$=\large{\frac{8}{7}}$ or $\large{1\frac{1}{7}}$.

If $\dfrac {3}{4}$ of $\dfrac {1}{2}$ of a number is $60$ then the number is:

  1. $160$

  2. $400$

  3. $500$

  4. $700$


Correct Option: A
Explanation:
let the number be $x$

now $\dfrac 34$ of $\dfrac 12$ of x is $60$

$\Rightarrow \dfrac { 3 }{ 4 } (\dfrac { 1 }{ 2 } (x))=60\\ \Rightarrow \dfrac { 3x }{ 8 } =60\\ \Rightarrow x=\dfrac { 60\times 8 }{ 3 } =160$ 

$\dfrac{\dfrac { 540 }{ 11 } \times 7}{343\dfrac { 7 }{ 11 }}$ 

  1. 1

  2. 2

  3. 3

  4. 4


Correct Option: A
Explanation:

$\begin{array}{l} In\, \, L.H.S \ No.=\frac { { 540\times 7 } }{ { 11 } } \times \frac { { 11 } }{ { \left( { 343\times 11+7 } \right)  } }  \ \frac { { 540\times 7 } }{ { 7\left( { { 7^{ 2 } }\times 11+1 } \right)  } }  \ No.=\frac { { 540 } }{ { 539+1 } } =1 \end{array}$

Whole number is 1.

The value of the expression $\sqrt {34-24\sqrt 2}\times (4+3\sqrt 2)$ is

  1. $-2$

  2. $2$

  3. $3$

  4. $4$


Correct Option: B
Explanation:

$\sqrt {34-24\sqrt 2}\times (4+3\sqrt 2)$


$=\sqrt {34-24\sqrt 2}\sqrt {(4+3\sqrt 2)^2}$

$=\sqrt {(34-24\sqrt 2)(16+18+24\sqrt 2)}$

$=\sqrt {(34-24\sqrt 2)(34+24\sqrt 2)}$

$=\sqrt {(34)^2(24\sqrt 2)^2}$

$=\sqrt {1156-1152}=\sqrt 4=2$

The product of two-fifths of a number and $80\%$ of another number is what percent of the product of the numbers

  1. $20\%$

  2. $24\%$

  3. $28\%$

  4. $32\%$


Correct Option: D

A certain number of men went to a hotel. Each man spent as many rupees as one-fourth of the men. If the total bill paid was Rs $20449$, then how many men visited in the hotel ?

  1. $286$

  2. $284$

  3. $281$

  4. $283$


Correct Option: A
Explanation:

Let the number of men visiting hotel be $x$


Money spent by one man $=\dfrac{1}{4}x$

Total bill $=20449$

$x\times \dfrac{1}{4}x=20449$

$x^2=81796$

$x=286\,men$.


Multiply $\dfrac{6}{13}$ by the reciprocal of $\dfrac{-7}{16}$

  1. $\dfrac{-95}{91}$

  2. $\dfrac{-96}{91}$

  3. $\dfrac{96}{91}$

  4. None of these


Correct Option: B
Explanation:
Reciprocal of $\dfrac{-7}{16}$ is $\dfrac{-16}{7}$

Now $\dfrac{6}{13}\times$ Reciprocal of $\dfrac{-7}{16}$

$=\dfrac{6}{13}\times\dfrac{-16}{7}$

$=\dfrac{6\times -16}{13\times 7}=\dfrac{-96}{91}$

If one-third of one-fourth of a number is $15$, then three-tenth of that number is:

  1. $75$

  2. $22$

  3. $18$

  4. $66$


Correct Option: C

Two-Third of a number and $\displaystyle \frac{25}{216}$ of its reciprocal are equal. What is the number?

  1. $\displaystyle \frac{25}{144}$

  2. $\displaystyle \frac{5}{12}$

  3. $\displaystyle \frac{144}{25}$

  4. $\displaystyle \frac{12}{5}$


Correct Option: B
Explanation:

Let the number be x Given $\displaystyle \frac{2}{3}x=\frac{25}{216}\times\frac{1}{x}$
$\displaystyle\Rightarrow x^{2}=\frac{25}{216 _{72}}\times\frac{3^{1}}{2}=\frac{25}{144}$
$\displaystyle\Rightarrow x=\sqrt{\frac{25}{144}}=\frac{5}{12}$

$\displaystyle \left ( 999\frac{999}{1000}\times 7 \right )$ is equal to 

  1. $\displaystyle 6993\frac{7}{1000}$

  2. $\displaystyle 7000\frac{7}{1000}$

  3. $\displaystyle 6633\frac{7}{1000}$

  4. $\displaystyle 6999\frac{993}{1000}$


Correct Option: D
Explanation:

Given expression $\displaystyle =\left ( 999+\frac{999}{1000} \right )\times7$
$\displaystyle=1000-1+1-\frac{1}{1000}\times7$
$\displaystyle=\left ( 1000-\frac{1}{1000} \right )\times7=7000-\frac{7}{1000}$
$\displaystyle=6999+1-\frac{7}{1000}=6999+\frac{993}{1000}$
$\displaystyle=6999\frac{993}{1000}$

The daily consumption of milk of a family is $\displaystyle 3\frac{1}{4}$ litres. The quantity of milk consumed by the family during the month of September 2003 is

  1. 90 lit

  2. $\displaystyle 100\frac{1}{2}$ lit

  3. $\displaystyle 97\frac{1}{2}$ lit

  4. none


Correct Option: C
Explanation:

Per day consumption $=3\cfrac14$liters.

There are $30$ days in the month of September.
So, Consumption in september $=30\times 3\cfrac14=30\times \cfrac {13}{4}=97\cfrac12$liters.
Option C is correct.

Consider the following statements : 
A. The product of an integer and a rational number can never be a natural number 
B. The quotient of division of an integer by a rational number can never be an integer
Which of the statements given above is/are correct ?

  1. A only

  2. B only

  3. Both A and B

  4. Neither A nor B


Correct Option: D
Explanation:

Let integer = 4 and Rational number = $\displaystyle \frac{2}{1} $
Then product = $\displaystyle 4\times\frac{2}{1}=8 $ (a natural number)
and Quotient = $\displaystyle 4\div \frac{2}{1}=4\times \frac{1}{2}=2 $ (an integer)

What would be the reciprocal of the sum of the reciprocal of the numbers $\displaystyle \frac{3}{5}$ and $\displaystyle \frac{7}{3}$?

  1. $\displaystyle \frac{1}{42}$

  2. $\displaystyle \frac{21}{44}$

  3. $\displaystyle \frac{4}{5}$

  4. $\displaystyle \frac{36}{55}$


Correct Option: B
Explanation:

Sum of the reciprocals of $\displaystyle \dfrac{3}{5}$ and $\dfrac{7}{3}$
$\displaystyle =\frac{5}{3}+\frac{3}{7}=\frac{35+9}{21}=\frac{44}{21}$
$\displaystyle \therefore $ Required number $\displaystyle =\frac{21}{44} $

Reciprocal of $\displaystyle \frac {7}{5}$ is

  1. $1\displaystyle \frac {2}{5}$

  2. $\displaystyle \frac {5}{7}$

  3. $5\displaystyle \frac {2}{3}$

  4. $\displaystyle \frac {12}{5}$


Correct Option: B
Explanation:

We know that the reciprocal of any number $n$ is $\dfrac {1}{n}$. When we multiply a number by its reciprocal, we get $1$ as the answer. For example: $n\times \dfrac { 1 }{ n } =1$ 


Therefore, the reciprocal of  the given fraction $\dfrac {7}{5}$ is as follows:

$\dfrac { 1 }{ \dfrac { 7 }{ 5 }  } =\dfrac { 5 }{ 7 } \quad \quad \quad \quad \quad \quad \quad \left{ \because \quad \dfrac { 1 }{ \dfrac { 1 }{ x }  } =\dfrac { x }{ 1 }  \right}$ 

Hence, the reciprocal of $\dfrac {7}{5}$ is $\dfrac {5}{7}$.

Reciprocal of $\displaystyle \frac{6}{3}$ is

  1. -$\displaystyle \frac{6}{3}$

  2. -$\displaystyle \frac{3}{6}$

  3. $\displaystyle \frac{3}{6}$

  4. $36$


Correct Option: C
Explanation:

The reciprocal of a number is $1$ divided by that number. For example, the reciprocal of $a$ is $\dfrac {1}{a}$


Now, we find the reciprocal of $\dfrac {6}{3}$ as follows:

$\dfrac { 1 }{ \dfrac { 6 }{ 3 }  } =\dfrac { 3 }{ 6 } \quad \quad \quad \quad \quad \quad \quad \left{ \because \quad \dfrac { 1 }{ \dfrac { 1 }{ x }  } =\dfrac { x }{ 1 }  \right}$ 

Hence, the reciprocal of $\dfrac {6}{3}$ is $\dfrac {3}{6}$

Reciprocal of $2 \displaystyle \frac{1}{3}$ is

  1. $\displaystyle \frac{7}{3}$

  2. $-\displaystyle \frac{7}{3}$

  3. $-\displaystyle \frac{3}{7}$

  4. $\displaystyle \frac{3}{7}$


Correct Option: D
Explanation:

We first rewrite the given mixed fraction $2\dfrac { 1 }{ 3 }$ as $\dfrac {7}{3}$. 


We know that the reciprocal of a number is $1$ divided by that number. For example, the reciprocal of $a$ is $\dfrac {1}{a}$
 

Now, we find the reciprocal of $\dfrac {7}{3}$ as follows:

$\dfrac { 1 }{ \dfrac { 7 }{ 3 }  } =\dfrac { 3 }{ 7 } \quad \quad \quad \quad \quad \quad \quad \left\{ \because \quad \dfrac { 1 }{ \dfrac { 1 }{ x }  } =\dfrac { x }{ 1 }  \right\}$ 

Hence, the reciprocal of $2\dfrac { 1 }{ 3 }$ is $\dfrac {3}{7}$

Reciprocal of $3$ is________.

  1. $-3$

  2. $-\displaystyle \frac{1}{3}$

  3. $\displaystyle \frac{1}{3}$

  4. None of these


Correct Option: C
Explanation:

The reciprocal of a number is $1$ divided by that number. For example, the reciprocal of $a$ is $\dfrac {1}{a}$


Hence, the reciprocal of $3$ is $\dfrac {1}{3}$

Ravi had $\displaystyle \frac {5}{6}$ of a cake. He ate $\displaystyle \frac {2}{3}$ of it. What part of the cake did he eat?

  1. $\displaystyle \frac {5}{9}$

  2. $\displaystyle \frac {10}{12}$

  3. $\displaystyle \frac {10}{6}$

  4. $\displaystyle \frac {10}{3}$


Correct Option: A
Explanation:

It is given that Ravi had $\dfrac {5}{6}$ of a cake and from that piece of cake he ate $\dfrac {2}{3}$rd of it which means that:


$\dfrac { 5 }{ 6 } \times \dfrac { 2 }{ 3 } \ =\dfrac { 5 }{ 3 } \times \dfrac { 1 }{ 3 } \ =\dfrac { 5 }{ 9 }$

Hence, Ravi ate $\dfrac {5}{9}$th part of the cake.

The product of a fractional number and its multiplicative inverse is

  1. $0$

  2. $1$

  3. number itself

  4. none


Correct Option: B
Explanation:

If the product of two numbers is $1$, then each number is known as multiplicative inverse or the reciprocal of one another. To find the multiplicative inverse of a proper or improper fraction, interchange the numerator and denominator. For example, the multiplicative inverse of the fraction $\dfrac {5}{18}$ is $\dfrac {18}{5}$.


Now, the product of the fractional number $\dfrac {5}{18}$ and its multiplicative inverse $\dfrac {18}{5}$ is as follows:

$\dfrac { 5 }{ 18 } \times \dfrac { 18 }{ 5 } =1$

Hence, the product of a fractional number and its multiplicative inverse is $1$.

The reciprocal of the fraction $\displaystyle  \frac { 5 }{ 11 }$ is

  1. $\displaystyle \frac { 11 }{ 5 }$

  2. $\displaystyle \frac { 5 }{ 11 }$

  3. $\displaystyle \frac { 1 }{ 5 }$

  4. $\displaystyle \frac { 1 }{ 11 }$


Correct Option: A
Explanation:

the reciprocal of 5/11 is 11/5..

$\displaystyle  \frac { 1 }{ 6 } $ of 48 liter = ........ liter 

  1. 7

  2. 1

  3. 8

  4. 6


Correct Option: C
Explanation:

1/6 of 48 liter

= (1/6)*48 liter
=8 liter

$\displaystyle 18\quad of\frac { 1 }{ 6 } $ is -

  1. $\displaystyle \frac { 1 }{ 108 } $

  2. 3

  3. -3

  4. None of these


Correct Option: B
Explanation:
Foundation chapter & CO
Given $18$ of $\dfrac{1}{6}$
$18\times \dfrac{1}{6}$
$\Rightarrow 3$

$\displaystyle  \frac { 2 }{ 4 }$ of a rupee = .......paise 

  1. 20

  2. 50

  3. 40

  4. 10


Correct Option: B
Explanation:

1 rupee=100 paise

so 2/4 of a rupee=(2/4)*100=50 paise

Two-fifth of $10$ litre $=$  _____ litres

  1. $2$

  2. $3$

  3. $4$

  4. $5$


Correct Option: C
Explanation:

$\dfrac{2}{5} $ of $10$ litre $=\dfrac{2}{5}\times 10=4$ litres.


Hence, the answer is $4$

The reciprocal of $15$ is ___.

  1. $15$

  2. $\displaystyle \frac{15}{1}$

  3. $\displaystyle \frac{1}{15}$

  4. $1$


Correct Option: C
Explanation:
In the reciprocal, the numerator and the denominator are interchanged.
So, the reciprocal of $15$ is $\dfrac{1}{15}$.
Hence, the answer is $\dfrac{1}{15}$.

The reciprocal of $6-\sqrt{5}$ is equal to

  1. $\dfrac{3-\sqrt{5}}{8}$

  2. $\dfrac{6+\sqrt{5}}{31}$

  3. $\dfrac{6+2\sqrt{5}}{41}$

  4. $\dfrac{6-2\sqrt{5}}{56}$

  5. $\dfrac{6+2\sqrt{5}}{56}$


Correct Option: B
Explanation:

The reciprocal of $6-\sqrt5$ is $\dfrac{1}{(6-\sqrt5)}$
Multiply and divide it by $6+\sqrt5$ , we get $\dfrac{6+\sqrt5}{(6+\sqrt5)(6-\sqrt5)} = \dfrac{6+\sqrt5}{31}$

Find the reciprocal of $\dfrac23 \div \dfrac{14}{15}$

  1. $\dfrac57$

  2. $\dfrac56$

  3. $\dfrac32$

  4. $\dfrac75$


Correct Option: D
Explanation:

$\dfrac{2}{3} \div \dfrac{14}{15} = \dfrac{2\times15}{3\times14}$


                $= \dfrac{30}{42}$

                $= \dfrac{5\times6}{7\times6}$

                $= \dfrac{5}{7}$

Reciprocal of $\dfrac{5}{7}$ is $\dfrac{7}{5}$

Multiply the following. Write the answer as a mixed fraction.
$\cfrac { 6 }{ 7 } \times 2$

  1. True

  2. False


Correct Option: A
Explanation:

$\dfrac{6}{7} \times 2$


Can be written as


$=\dfrac{12}{7} $

$=1\dfrac{5}{7} $

Find the following product:
$6\times \cfrac { 1 }{ 5 } $


$1\cfrac { 2 }{ 5 } $

  1. True

  2. False


Correct Option: B

Rehna works $2\cfrac { 1 }{ 2 } $ hours each day on her embroidery. She completes the work in $7$ days. How many hours did she take to complete her work?


Ans : $17\cfrac { 1 }{ 2 } $ hrs.

  1. True

  2. False


Correct Option: A
Explanation:

Rehana works $2\dfrac{1}{2}$ hrs $= 150 $minutes


As she completed her work in $7$ days,

$150 \times 7 = 1050$ minutes = $\dfrac{1050}{60}$ hours

$=\dfrac{35}{2}$ hours $=17\dfrac{1}{2}$ hours


So, Rehana took $17\dfrac{1}{2}$ hours to complete her work.

Multiply and reduce to lowest form:
$\cfrac { 2 }{ 3 } \times 5\cfrac { 1 }{ 5 } $

  1. $3\cfrac { 7 }{ 15 } $

  2. $7\cfrac { 3 }{ 15 } $

  3. $\cfrac { 7 }{ 15 } $

  4. $3\cfrac { 3 }{ 15 } $


Correct Option: A
Explanation:

$\dfrac{2}{3}\times 5\dfrac{1}{5}$


Can be written as


$\dfrac{2}{3}\times \dfrac{26}{5}$

$=\dfrac{52}{15}$

$=3\dfrac{7}{15}$

Deepak can paint $\cfrac { 2 }{ 5 } $ of a house in one day. If he continuous working at this rate, how many days will he take to paint the whole house?

  1. $2\cfrac { 1 }{ 2 } $ days

  2. $1\cfrac { 1 }{ 2 } $ days

  3. $\cfrac { 1 }{ 2 } $ days

  4. $2\cfrac { 1 }{ 4 } $ days


Correct Option: A
Explanation:

$\boxed{\text{Work(W)}\propto \text{Days(D)}\\dfrac{W _1}{D _1}=\dfrac{W _2}{D _2}}$

given,
$W _1=\dfrac25\quad D _1=1\,\text{day}\W _2=1\,\,\text{(painting the whole house)}$
to find, $D _2=?$

$\dfrac{2/5}{1}=\dfrac{1}{D _2}\Rightarrow D _2=\dfrac52$

$\therefore D _2=2\dfrac12 \,\text{days}$

The value of $(1024)^{-\dfrac {4}{5}}$ is ________.

  1. $\left (\dfrac {1}{4}\right )^{3}$

  2. $\left (\dfrac {1}{4}\right )^{2}$

  3. $\dfrac {1}{256}$

  4. $\dfrac {1}{512}$


Correct Option: C
Explanation:

$1024=2\times2\times2\times2\times2\times2\times2\times2\times2\times2 = 2^{10}$


To find,
$(1024)^{-\dfrac{4}{5}} = 2^{-\dfrac{10\times4}{5}}$ 
                   $= 2^{-8}$

$2^{8}= 2\times2\times2\times2\times2\times2\times2\times2 = 256$

$\therefore (1024)^{-\dfrac{4}{5}} = \dfrac{1}{256}$

When simplified, the product $\left( 1-\cfrac { 1 }{ 3 }  \right) \left( 1-\cfrac { 1 }{ 4 }  \right) \left( 1-\cfrac { 1 }{ 5 }  \right) ...\left( 1-\dfrac 1n \right) $ becomes

  1. $\dfrac { 1 }{ n } $

  2. $\dfrac { 2 }{ n } $

  3. $\dfrac { 2(n-1) }{ n } $

  4. $\dfrac { 2 }{ n(n+1) } $


Correct Option: B
Explanation:

$\left( 1-\cfrac { 1 }{ 3 }  \right) \left( 1-\cfrac { 1 }{ 4 }  \right) \left( 1-\cfrac { 1 }{ 5 }  \right) ...\left( 1- \cfrac 1n \right) =\cfrac { 2 }{ 3 } .\cfrac { 3 }{ 4 } .\cfrac { 4 }{ 5 } ....\cfrac { n-2 }{ n-1 } .\cfrac { n-1 }{ n } =\cfrac { 2 }{ n } $

$4\frac{4}{5}\div\frac{3}{5}$ of $5+\frac{4}{5}\times\frac{3}{10} -\frac{1}{5}$ is simplified, then the result is

  1. $1\frac{16}{25}$

  2. $1\frac{17}{25}$

  3. $\frac{40}{25}$

  4. $\frac{42}{25}$


Correct Option: A
Explanation:

Apply BODMAS
$4\frac{4}{5}\div\frac{3}{5}$ of $5+\frac{4}{5}\times\frac{3}{10} -\frac{1}{5}$
$=\frac{24}{5}\div3+\frac{4}{5\times\frac{3}{10}-\frac{1}{5}}$
$=\frac{8}{5}+\frac{6}{25}-\frac{1}{5}$
$=\frac{41}{25}$
$=1\frac{16}{25}$
Option 'A' is the answer

$\left( 1-\dfrac {1}{3} \right) \left( 1-\dfrac {1}{4} \right) \left( 1-\dfrac {1}{5} \right) ....\left( 1-\dfrac {1}{n} \right) $ equals

  1. $\dfrac {1}{n}$

  2. $\dfrac {2}{n}$

  3. $\dfrac {3}{n}$

  4. $\dfrac {4}{n}$


Correct Option: B
Explanation:

$\quad \left( 1-\cfrac { 1 }{ 3 }  \right) \left( 1-\cfrac { 1 }{ 4 }  \right) \left( 1-\cfrac { 1 }{ 5 }  \right) ...=\cfrac { 2 }{ 3 } .\cfrac { 3 }{ 4 } .\cfrac { 4 }{ 5 } ...\cfrac { n-1 }{ n } =\cfrac { 2 }{ n } $

The product of the reciprocals of $\dfrac {x + 3}{x + 2}$ and $\dfrac {x^{2} -4}{x^{2} - 9}$ is

  1. $\dfrac {1}{(x -3)(x - 2)}$

  2. $\dfrac {x - 2}{x - 3}$

  3. $\dfrac {x - 3}{x - 2}$

  4. $(x - 3)(x - 2)$


Correct Option: C
Explanation:
The reciprocal of $\cfrac {x + 3}{x + 2}$ is $\cfrac {x + 2}{x + 3}$ 
And the reciprocal of $\cfrac {x^{2} -4}{x^{2} - 9}$ is $\cfrac {x^{2} -9}{x^{2} - 4}$
$\Rightarrow \cfrac {x^{2} -9}{x^{2} - 4} = \cfrac {(x-3)(x+3)}{(x-2)(x+2)}$
$\Rightarrow \cfrac {(x + 2)}{(x + 3)} \times \cfrac {(x - 3)}{(x - 2)}\times \cfrac {(x + 3)}{(x + 2)} = \cfrac {x - 3}{x - 2}$.

The value of $\large{\frac{1}{3}} \ of\ \large{4\frac{2}{3}}$ $\div$ $\large{2\frac{1}{3}} of\ \large{1\frac{1}{2}}$ is

  1. 1

  2. 2

  3. 3

  4. None of these


Correct Option: D
Explanation:

$\large{\frac{1}{3}} \ of\ \large{4\frac{2}{3}}$ $\div$ $\large{2\frac{1}{3}} of\ \large{1\frac{1}{2}}$



$=\dfrac13\times4\dfrac23\div2\dfrac13\ of\ \dfrac12$


$=\dfrac{14}{9}\div\dfrac73\ of\ \dfrac32$


$=\dfrac{14}{9}\div\dfrac73\times\dfrac32$


$=\dfrac{14}{9}\div\dfrac72$


$=\dfrac{14}{9}\times\dfrac27$


$=\dfrac49$


$\text{option D (None of these) is correct}$

Product of $\displaystyle \frac{12}{24}$ and $\displaystyle \frac{36}{72}$ is:

  1. $\displaystyle \frac{16}{24}$

  2. $\displaystyle \frac{3}{5}$

  3. $4$

  4. $\displaystyle \frac{1}{4}$


Correct Option: D
Explanation:

Product of the fraction is $\dfrac{12}{24}$ and $\dfrac{36}{72}$ is 

$\dfrac{12}{24} \times \dfrac{36}{72} = \dfrac{432}{1728} $ 
After simplifying, $\dfrac{432}{1728}$ can also be written as $\dfrac{1}{4}$.
Hence, the answer is $\dfrac{1}{4}$.

Product of $\displaystyle\frac{11}{12}\times \frac{16}{4}\times \frac{9}{16}$ is 

  1. $\displaystyle 2\frac{1}{16}$

  2. $\displaystyle \frac{3}{4}$

  3. $\displaystyle \frac{2}{8}$

  4. $\displaystyle \frac{9}{6}$


Correct Option: A
Explanation:

The product of $\dfrac{11}{12} \times \dfrac{16}{4} \times \dfrac{9}{16} $ is

$=\dfrac{11\times 16\times 9}{12\times 4\times 16}=\dfrac{33}{16}$ 
This can also be written as $\dfrac{32+1}{16}=2\dfrac{1}{16}$.
Hence, the answer is $2\dfrac{1}{16}$.

Reciprocal of $\displaystyle \frac{7}{5}$

  1. $\displaystyle 1\frac{2}{5}$

  2. $\displaystyle \frac{5}{7}$

  3. $\displaystyle 5\frac{2}{3}$

  4. $\displaystyle \frac{12}{5}$


Correct Option: B
Explanation:
In the reciprocal, numerator and denominator interchanges
So, the reciprocal of $\dfrac{7}{5}$ is $\dfrac{5}{7}$.
Hence, the answer is $\dfrac{5}{7}$.

$\displaystyle \frac{1}{9}$ of ___ $= 5$

  1. $5$

  2. $9$

  3. $14$

  4. $45$


Correct Option: D
Explanation:

$\dfrac{1}{9}$ of $45=5$ because $45$ is divided by $9$ in $5$ times.

Hence, the answer is $45$.

Find the product:

$\displaystyle 1\frac{1}{3}\times 3\frac{1}{4}\times \frac{7}{8}$

  1. $\displaystyle 3\frac{18}{24}$

  2. $\displaystyle 2\frac{19}{24}$

  3. $\displaystyle 3\frac{19}{24}$

  4. $\displaystyle 2\frac{18}{24}$


Correct Option: C
Explanation:

Let's first convert the mixed fraction into simple fraction $\dfrac{4}{3},$ $\dfrac{13}{4},$ $\dfrac{7}{8}$ .

The product is 
$\dfrac{4}{3} \times \dfrac{13}{4}\times \dfrac{7}{8}=\dfrac{91}{24}$
This can also be written as $3\dfrac{19}{24}$.

If $\displaystyle 40-\frac{1}{5}\times $ ____ $= 0$, then the missing value is 

  1. $0$

  2. $\displaystyle \frac{1}{5} $

  3. $\displaystyle \frac{199}{5} $

  4. $200$


Correct Option: D
Explanation:
Let missing value is $x$

$40$ $-\dfrac{1}{5}\times x=0$

$40$ $=\dfrac{1}{5}\times x$

$x=200$

Hence, the answer is $200$.

If the reciprocal of $y - 1$ is $y + 1$, then $y$ equals

  1. $-1$

  2. $+1$

  3. $0$

  4. $\pm$ 1

  5. none of these


Correct Option: E
Explanation:

Reciprocal of $y-1$ is $\dfrac{1}{y-1} = y+1$, so we get ${y}^{2}-1=1$
Which implies $y = \pm \sqrt2$
So, the correct option is $E$.

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