0

Simplest ratio - class-VII

Attempted 0/58 Correct 0 Score 0

Simplify: $\dfrac{{4 + \sqrt 5 }}{{4 - \sqrt 5 }} + \dfrac{{4 - \sqrt 5 }}{{4 + \sqrt 5 }}$

  1. $\dfrac {42}{11}$

  2. $\dfrac {40}{11}$

  3. $\dfrac {39}{25}$

  4. $\dfrac {16}{25}$


Correct Option: A
Explanation:

$\dfrac{4+\sqrt5}{4-\sqrt5} = \dfrac{(4+\sqrt5)}{(4-\sqrt5)} \dfrac{(4+\sqrt5)}{(4+\sqrt5)}$    ...... rationalizing numerator and the denominator


$= \dfrac{(4+\sqrt5)^2}{16-5} = \dfrac{(4+\sqrt5)^2}{11} $

$\dfrac{4-\sqrt5}{4+\sqrt5} = \dfrac{(4-\sqrt5)}{(4+\sqrt5)} \dfrac{(4-\sqrt5)}{(4-\sqrt5)}$    ...... rationalizing numerator and the denominator, 

$= \dfrac{(4-\sqrt5)^2}{16-5} = \dfrac{(4-\sqrt5)^2}{11} $


$\dfrac{4+\sqrt5}{4-\sqrt5} +\dfrac{4-\sqrt5}{4+\sqrt5} = \dfrac{(4+\sqrt5)^2 +(4-\sqrt5)^2}{11} =\dfrac{16+5+16+5}{11} = \dfrac{42}{11}$

What fraction of a day is $16$ hours?

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

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

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

  4. $\dfrac{16}{60}$


Correct Option: C
Explanation:

A complete day has $24$ hours so

$Required\>ratio\>=\>\dfrac{16}{24}\>=\>\dfrac23$

Hence option $'C'$ is the answer.

Which of the following are true?

(a) $\displaystyle \frac{35}{16}=2.1875$
(b) $\displaystyle \frac{17}{8}=2.125$
(c) $\displaystyle \frac{327}{500}=0.654$
(d) $\displaystyle \frac{14588}{625}=23.3408$

  1. $a,b,c,d$

  2. $a,c,d$

  3. $a,b,c$

  4. $a,b,d$


Correct Option: A
Explanation:

(i) $\displaystyle \frac{35}{16} = \frac{35 \times 5^4}{2 \times 5^4}= \frac{35 \times 625}{(10)^4}= \frac{21875}{10000}=2.1875$
(ii) $\displaystyle \frac{17}{8} = \frac{17 \times 5^3}{2^3 \times 5^3} = \frac{17 \times 125}{(10)^3}=\frac{2125}{1000}=2.125$
(iii) $\displaystyle \frac{327}{500} = \frac{327}{5\times 5 \times 5 \times 2 \times 2}$
$=\displaystyle \frac{327}{5^3 \times 2^2} = \frac{327}{5^3 \times 2^3}= \frac{654}{(10)^3} = 0.654$
(iv) $\displaystyle \frac{14588}{625} = \frac{2^2 \times 7 \times 521}{5^4} = \frac{2^6 \times 7 \times 521}{2^4 \times 5^4}$
$\displaystyle =\frac{233408}{10^4}=23.3408$

Solve: $8\dfrac{2}{3}+9\dfrac{3}{8}$

  1. $40$

  2. $\dfrac{433}{24}$

  3. $24$

  4. $\dfrac{437}{24}$


Correct Option: B
Explanation:

Given, $\displaystyle 8\frac{2}{3} + 9\frac{3}{8}$


Could be written as,


$\displaystyle \frac{26}{3} + \frac{75}{8}$

LCM of 3 and 8 is 24,

= $\displaystyle \dfrac{208}{24} + \dfrac{225}{24}$

= $\displaystyle\dfrac{433}{24}$

Three number $ A, B$ and $C$ are in the ratio of $12 : 15 : 25 .$ If the some of these numbers be $364$ find the ratio between the difference of $B$ and $A$ and the difference of $C$and $B ?$

  1. $3 : 2$

  2. $3 : 10$

  3. $3 : 5$

  4. $4 : 2$


Correct Option: B
Explanation:

Let $A=12k,B=15k, C=25k$

Now $A+B+C=364$
$12k+15k+25k=364$
$52k=364$
$k=\dfrac{364}{52}=7$
$\dfrac{B-A}{C-B}=\dfrac{15k-12k}{25k-15k}=\dfrac{3k}{10k}=\dfrac{3}{10}$
Hence the correct option is (B).

The standard from of a rational number -225 / 465 is 

  1. $\frac { -4 }{ 7 } $

  2. $\frac { -6 }{ 7 } $

  3. $\frac { -6 }{ 17 } $

  4. none of these


Correct Option: D
Explanation:

$\dfrac{-225}{465}=\dfrac{-45}{93}=-\dfrac{15}{31}$


Thus, option D is correct.

Which of the following numbers is in standard form?

  1. $\dfrac { -24 }{ 52 } $

  2. $\dfrac { -49 }{ 71 } $

  3. $\dfrac { -27 }{ 48 } $

  4. $\dfrac { 28 }{ -105 } $


Correct Option: B
Explanation:
Here option $A) \frac{-24}{52}=\frac{-6}{13}$

$B) \frac{-49}{71}$

$C) \frac{-27}{48}=\frac{-9}{16}$

$D) \frac{28}{-105}=\frac{4}{-15}$

Here (B) is in the standard form.

State whether true or false
Simplest form of the ratio 
225% in form of ratio is $\displaystyle \frac{9}{4}$

  1. True

  2. False


Correct Option: A
Explanation:

Given percentage is $ 225 % $

In fraction form, $ 225  % $ $  = \dfrac {225}{100} $

Simplifying it by dividing the numerator and denominator by $ 25  $, we get the fraction $ = \dfrac {9}{4} $

If $2a-5b = 0$ then find the value of $\displaystyle \frac{a+b}{a-b}$.

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

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

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

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


Correct Option: B
Explanation:

Given, $ 2a-5b = 0 $

$=>2a = 5b $

$ => \dfrac {a}{b} = \dfrac {5}{2} $

Applying componendo and dividendo,

Now, $ \dfrac {a+b}{a-b} = \dfrac{5+2}{5-2} =

\dfrac {7}{3} $

If $2a-5b = 0$ then find the value of  $\displaystyle \frac{a-b}{b}$

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

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

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

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


Correct Option: B
Explanation:

Given, $ 2a-5b = 0 $
$=> 2a = 5b $
$ => \dfrac {a}{b} = \dfrac {5}{2} $
 
Now, $ \dfrac {a-b}{b} = \dfrac {a}{b} - 1 = \dfrac {5}{2} - 1 = \dfrac{5-2}{2} = \dfrac {3}{2} $

State true or false.
If $5m-n=m+2n$ then the value of $(4m + n) : (4m - n)$ is $2:1$

  1. True

  2. False


Correct Option: A
Explanation:

$ 5m-n=m+2n \$
$ => 4m = 3n \$
$ => \dfrac {m}{n} = \dfrac {3}{4} \$
$ => m : n = 3:4 $

Let $ m = 3a ; n = 4a $


So, $ (4m + n) : (4m - n) = 4(3a) + 4a : 4(3a) -4a $


$ => (4m + n) : (4m - n) = 16a:8a = 2: 1 $

If $2a-5b = 0$ then find the value of  $\displaystyle \frac{a+b}{b}$

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

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

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

  4. $\displaystyle \frac{7}{6}$


Correct Option: A
Explanation:

Given, $ 2a-5b = 0 $
$=>. 2a = 5b $
$ => \frac {a}{b} = \frac {5}{2} $
 
Now, $ \frac {a+b}{b} = \frac {a}{b} + 1 = \frac {5}{2} + 1 = \frac{5+2}{2} = \frac {7}{2} $

If a : b = 7 : 8 and b : c = 12 : 7 then find a : c in the simplest form is 3:2

  1. True

  2. False


Correct Option: A
Explanation:

In the given ratios "b" is

the common term, and the values of b in both ratios are not equal.





To make them equal, find the L.C.M.

of values corresponding to b i.e., $ 8 $ and $ 12 $.





L.C.M. of $ 8  $ and $ 12 = 24 $





Therefore, an equivalent ratio of $ a:b $ such that $ b = 24 $ is $= 7 \times 3:8 \times 3 = 21:24 $





Similarly, an equivalent ratio of $ b:c$ is $ = 12 \times 2 :7 \times 2 = 24:14 $





Therefore,$ a: c = 21:14 $

Dividing by $ 7 $

$ a:c = 3:2 $

Find the value of $\left( \sqrt { 169-144 }  \right) \div \left( \sqrt { 64+36 }  \right) $

  1. 0.5

  2. 0.25

  3. 2.5

  4. 5


Correct Option: A
Explanation:

$\left( \sqrt { 169-144 }  \right) \div \left( \sqrt { 64+36 }  \right) \ =\sqrt { 25 } \div \sqrt { 100 } =5\div 10=\displaystyle\frac { 5 }{ 10 } =0.5$

$\displaystyle \frac {2}{5}\, =\, \displaystyle \frac {?}{15}$

  1. 2

  2. 3

  3. 5

  4. 6


Correct Option: D
Explanation:

$\displaystyle \frac {2}{5}\, =\, \displaystyle \frac {2}{5}\, \times\, \displaystyle \frac {3}{3}\, =\, \displaystyle \frac {6}{15}$

The fraction equivalent to $\displaystyle \frac {1}{2}$ is

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

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

  3. $\displaystyle \frac {8}{16}$

  4. All the above


Correct Option: D
Explanation:

$\displaystyle \frac {1}{2}\, =\, \displaystyle \frac {1\, \times\, 2}{2\, \times\, 2}\, =\, \displaystyle \frac {2}{4}$


$\displaystyle \frac {1}{2}\, =\, \displaystyle \frac {1\, \times\, 3}{2\, \times\, 3}\, =\, \displaystyle \frac {3}{6}$

$\displaystyle \frac {1}{2}\, =\, \displaystyle \frac {1\, \times\, 8}{2\, \times\, 8}\, =\, \displaystyle \frac {8}{16}$

So $\displaystyle \frac {1}{2}\, =\, \displaystyle \frac {2}{4}\, =\, \displaystyle \frac {3}{6}\, =\, \displaystyle \frac {8}{16}$

The fraction equivalent to $\displaystyle \frac {1}{2}$ is .......... 

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

  2. $\displaystyle \frac {5}{10}$

  3. $\displaystyle \frac {9}{8}$

  4. All the above


Correct Option: D
Explanation:

$\displaystyle \frac {1}{2}\, =\, \displaystyle \frac {3}{6}\, =\, \displaystyle \frac {5}{10}\, =\, \displaystyle \frac {9}{18}$

$\displaystyle \frac {15}{45}\, =\, \displaystyle \frac {?}{9}$

  1. 15

  2. 9

  3. 5

  4. 3


Correct Option: D
Explanation:

$\displaystyle \frac {15}{45}\, =\, \displaystyle \frac {15\, \div\, 5}{45\, \div\, 5}\, =\, \displaystyle \frac {3}{9}$

Convert 0.225 in to form p/q

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

  2. $\displaystyle \frac{9}{40}$

  3. $\displaystyle \frac{9}{50}$

  4. $\displaystyle \frac{9}{400}$


Correct Option: B
Explanation:

${.225}\Rightarrow \frac{225}{1000}=\frac{9}{40}$

$1.\bar{3}$ is equal to

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

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

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

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


Correct Option: C
Explanation:

$1.\bar{3}$
Let $1.3333...$ be $x$
$1.3333...=x$  {i}
$13.333...=10x$ {ii} [Multiplied by $10$]
                               
$        12  =9x$
$=>x=\frac{12}{9}$
$=>x=\frac{4}{3}$

The fraction form of 0.23 is

  1. $\displaystyle\frac{2.3}{10}$

  2. $\displaystyle\frac{23}{100}$

  3. $\displaystyle\frac{23}{90}$

  4. $\displaystyle\frac{7}{90}$


Correct Option: B
Explanation:

The fraction for of 0.23$ =\frac{23}{100}$
Hence $B$  is the answer

The rational form of $-25.6875$ is

  1. $\displaystyle-\frac{411}{16}$

  2. $\displaystyle-\frac{421}{16}$

  3. $\displaystyle-\frac{431}{16}$

  4. $\displaystyle-\frac{441}{16}$


Correct Option: A
Explanation:

Consider the given decimal number

$ \Rightarrow -25.6875 $

$ \Rightarrow -\dfrac{256875}{10000} $

$ \Rightarrow -\dfrac{51375}{2000} $

$ \Rightarrow -\dfrac{10275}{400} $

$ \Rightarrow -\dfrac{2055}{80} $

$ \Rightarrow -\dfrac{411}{16} $


Hence, this is the answer.

The lowest form of $\displaystyle \frac { 30 }{ 60 } $ is -

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

  2. $\displaystyle \frac { 6 }{ 12 } $

  3. $\displaystyle \frac { 15 }{ 30 } $

  4. $\displaystyle \frac { 10 }{ 20 } $


Correct Option: A
Explanation:

lowest form of 30/60 is

30/60=3/6=1/2

Decimal for $79\%$ is  ____ 

  1. $7.9$

  2. $0.79$

  3. $79.00$

  4. $1.79$


Correct Option: B
Explanation:

$79\% = 0.79$ in decimal form. Percent means 'per $100$'. 


So, $79\%$ means $79$ per $100$ or simply $\dfrac{79}{100}$.

If you divide $79$ by $100$, you'll get $0.79$ (a decimal number).

So option B is the correct answer.

$\displaystyle \frac { 20 }{ 25 } = \frac {?} {5} $

  1. $2$

  2. $5$

  3. $4$

  4. $6$


Correct Option: C
Explanation:

$\displaystyle \frac { 20 }{ 25 } =\frac { 20\div 5 }{ 25\div 5 } =\frac { 4 }{ 5 }  $

$\displaystyle \frac{68}{100} = $ ..............%

  1. 0.68

  2. 6.8

  3. 68

  4. 68.01


Correct Option: C
Explanation:

Here, we have to covert fraction in to percentage.

We know that, to covert number into percentage we have to multiply the given number by $100.$
$\Rightarrow$  $\dfrac{68}{100}\times 100=68\%$

$0.97$ is equal to .............$\%$

  1. $9.7$

  2. $9.71$

  3. $97$

  4. $0.97$


Correct Option: C
Explanation:
Multiply both numerator and denominator by $100$ in the given value to find the percentage value.

$\dfrac{0.97×100}{100}=\dfrac{97}{100}= 97\%$

So option C is the correct answer.

The fraction equivalent to $\displaystyle \frac {1} {3} $ is ................

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

  2. $\displaystyle \frac {5} {15} $

  3. $\displaystyle \frac {6} {18} $

  4. All the above


Correct Option: D
Explanation:

3×3=9 so 3/9=1/3

5×3=15 so 5/15=1/3
6×3=18 so 6/18=1/3
So all the given options are equivalent to 1/3
Option D is the correct answer.

Which number should come in place of $\displaystyle \ \Box, \dfrac { 1 }{ 4 } +\dfrac { 2 }{ 4 } +\dfrac { \Box  }{ 4 } =1\dfrac { 1 }{ 2 } $

  1. $1$

  2. $2$

  3. $3$

  4. $4$


Correct Option: C
Explanation:

$=\displaystyle \frac { 3 }{ 2 } -\frac { 1 }{ 4 } -\frac { 2 }{ 4 }=  \frac { 6-1-2 }{ 4 }= \frac{3} {4} $ 

What is the value of $\dfrac {1}{1 + \sqrt {2} + \sqrt {3}} + \dfrac {1}{1 - \sqrt {2} + \sqrt {3}}$?

  1. $1$

  2. $\sqrt {2}$

  3. $\sqrt {3}$

  4. $2$


Correct Option: A
Explanation:

The value of $\dfrac {1}{(1 + \sqrt {3})+\sqrt {2}} + \dfrac {1}{(1 + \sqrt {3}) - \sqrt {2}}$ is
$=\dfrac {(1 + \sqrt {3} - \sqrt {2}) + (1 + \sqrt {3} + \sqrt {2})}{(1 + \sqrt {3})^{2} - (\sqrt {2})^{2}}$
$= \dfrac {2(1 + \sqrt {3})}{1 + 3 + 2\sqrt {3} - 2}$
$= \dfrac {2(1 + \sqrt {3})}{2(1 + \sqrt {3})} = 1$

Reduce fraction to lowest form:
$\dfrac{144}{36}$

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

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

  3. $\dfrac{1}{36}$

  4. $\dfrac{4}{9}$


Correct Option: A
Explanation:

$\dfrac{144}{36}$


Dividing numerator and denominator by $12$, we get
$\dfrac{144}{36} = \dfrac{12}{3}$

Dividing both numerator and denominator again by $3$, we get

$\dfrac{12}{3} = \dfrac{4}{1}$

This is the lowest form

Reduce fraction to lowest form:
$\dfrac{100}{200}$

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

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

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

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


Correct Option: A
Explanation:

$\dfrac{100}{200}$


Dividing numerator and denominator by $100$, we get
$\dfrac{100}{200} = \dfrac{1}{2}$

This is the lowest form

Reduce fraction to lowest form:
$\dfrac{12}{16}$

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

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

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

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


Correct Option: A
Explanation:

$\dfrac{12}{16}$


Dividing numerator and denominator by $4$, we get
$\dfrac{12}{16} = \dfrac{3}{4}$

This is the lowest form

Reduce fraction to lowest form:
$\dfrac{125}{625}$

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

  2. $\dfrac{12}{625}$

  3. $\dfrac{5}{625}$

  4. $\dfrac{15}{25}$


Correct Option: A
Explanation:

$\dfrac{125}{625}$


Dividing numerator and denominator by $25$, we get
$\dfrac{125}{625} = \dfrac{5}{25}$

Dividing again both numerator and denominator by $5$, we get

$\dfrac{5}{25} = \dfrac{1}{5}$

This is the lowest form

Reduce fraction to lowest form:
$\dfrac{25}{100}$

  1. $\dfrac{25}{10}$

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

  3. $\dfrac{5}{10}$

  4. $\dfrac{5}{100}$


Correct Option: B
Explanation:

$\dfrac{25}{100}$


Dividing numerator and denominator by $25$, we get
$\dfrac{25}{100} = \dfrac{1}{4}$

This is the lowest form

Reduce fraction to lowest form:
$\dfrac{81}{36}$

  1. $\dfrac{18}{2}$

  2. $\dfrac{1}{36}$

  3. $\dfrac{8}{36}$

  4. $\dfrac{9}{4}$


Correct Option: D
Explanation:

$\dfrac{81}{36}$


Dividing numerator and denominator by $9$, we get
$\dfrac{81}{36} = \dfrac{9}{4}$

This is the lowest form

Which of these statements is CORRECT?

  1. $\dfrac {3}{6}$ and $\dfrac {1}{2}$ are equivalent fractions

  2. $\dfrac {1}{2}$ of an hour is equal to $20$ minutes

  3. $\dfrac {5}{6}$ is equal to $\dfrac {6}{5}$

  4. $1\ mm$ is $\dfrac {1}{100}$ of $1\ cm$


Correct Option: A
Explanation:

(A) $\dfrac {3}{6} = \dfrac {3\div 3}{6\div 3} = \dfrac {1}{2}$
(B) $\dfrac {1}{2}$ of an hour $= \dfrac {1}{2}\times 60$ minutes = $30$ minutes
(C) $\dfrac {5}{6} = 0.8333, \dfrac {6}{5} = 1.2$
$\therefore \dfrac {5}{6}\neq \dfrac {6}{5}$
(D) $\dfrac {1}{100}$ of $1$ cm = $\dfrac {1}{100}\times 10$ mm = $\dfrac {1}{10}$ mm.

Hence the correct answer is option A.

A fraction $\displaystyle\frac{x}{y}$ can be expressed as a terminating decimal if y has no prime factors other than _________.

  1. $2, 3$

  2. $3, 5$

  3. $2, 5$

  4. $2, 3, 5$


Correct Option: C
Explanation:

If the denominator has a prime factor $2$ or $5$ then it is a terminating decimal

Hence the correct answer is option C

The value of $\left(\displaystyle 1-\frac{1}{3}\right)\left(\displaystyle 1-\frac{1}{4}\right)\left(\displaystyle 1-\frac{1}{5}\right)\left(\displaystyle 1-\frac{1}{6}\right).....\left(\displaystyle 1-\frac{1}{n}\right)$ is _________.

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

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

  3. $\displaystyle\frac{2(n-1)}{4}$

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


Correct Option: B
Explanation:
We need to find value of $\left(1-\dfrac {1}{3}\right)\left (1-\dfrac {1}{4}\right)\left (1-\dfrac {1}{5}\right)\left(1-\dfrac {1}{6}\right).....\left (1-\dfrac {1}{n}\right)$
Solving each bracket, we get 
$\dfrac{2}{3} \times \dfrac{3}{4} \times \dfrac{4}{5} . . . . ...\dfrac{n-3}{n-2}\times \dfrac{n-2}{n-1} \times \dfrac{n-1}{n}$
Starting from $1^{st}$ term each denominator is cancelled out by next numerator.
Finally, we get $\dfrac{2}{n}$

The product of the $9$ fractions $\left(\displaystyle 1-\frac{1}{2}\right)\left(\displaystyle 1-\frac{1}{3}\right)\left(\displaystyle 1-\frac{1}{4}\right)..........\left(\displaystyle 1-\frac{1}{10}\right)=$____________.

  1. $\displaystyle\frac{10}{11}$

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

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

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


Correct Option: C
Explanation:
We need to simplify $\left (1-\dfrac {1}{2}\right)\left (1-\dfrac {1}{3}\right)\left (1-\dfrac {1}{4}\right).....\left (1-\dfrac {1}{10}\right)$
Simplifying each bracket, we get
$\dfrac{1}{2} \times \dfrac{2}{3} \times \dfrac{3}{4} . . . . ...\dfrac{7}{8}\times \dfrac{8}{9} \times \dfrac{9}{10}$
As we can see 
Starting from $1^{st}$ term, each denominator is cancelled out by next numerator.
Finally we get $\dfrac{1}{10}$

The standard form of $\displaystyle\frac{192}{-168}$ is _________.

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

  2. $\displaystyle\frac{-8}{7}$

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

  4. $\displaystyle\frac{-6}{7}$


Correct Option: B
Explanation:

the standard form of $ - \dfrac{192}{168}$

$=-\dfrac{2 \times 3\times 4\times 8}{2\times 3\times 4\times 7}$
$-\dfrac{8}{7}$

Which of the following sum is in the simplest form?

  1. $\dfrac{4}{9}+\dfrac{-5}{9}$

  2. $\dfrac{-2}{5}+\dfrac{13}{20}$

  3. $\dfrac{-5}{12}+\dfrac{11}{-12}$

  4. $\dfrac{-7}{8}+\dfrac{1}{12}+\dfrac{2}{3}$


Correct Option: A
Explanation:
A. $\dfrac{4}{9} + \dfrac{-5}{9} = \dfrac{-1}{9}$ Simplest Form

B. $\dfrac{-2}{5} + \dfrac{13}{20} = \dfrac{-8+13}{20} = \dfrac{5}{20}$ Not the simplest form

C. $\dfrac{-5}{12} + \dfrac{11}{-12} = \dfrac{-5-11}{12} = \dfrac{-16}{12}$ Not the simplest form

D. $\dfrac{-7}{8} + \dfrac{1}{12} + \dfrac{2}{3} = \dfrac{-21+2+16}{24} = \dfrac{-3}{24}$ Not the simplest form

$\Rightarrow$ Only A gives answer in simplest form

Which of the following is not equivalent to $\dfrac{4}{8}$ ?

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

  2. $\cfrac { 16 }{ 32 } $

  3. $1$

  4. $\cfrac { 12 }{ 24 } $


Correct Option: C
Explanation:

we have, $\dfrac{4}{8}=$ $\dfrac{1}{2}=$$\dfrac{16}{32}=$$\dfrac{12}{24}$

Among the given values, the one which is not equivalent to $\dfrac{4}{8}$ is 1.

Simplify: $\dfrac{5}{11} + 4\dfrac{3}{9} $

  1. $\dfrac{158}{33}$

  2. $\dfrac{168}{33}$

  3. $\dfrac{178}{33}$

  4. $\dfrac{148}{33}$


Correct Option: A
Explanation:
$\displaystyle \frac{5}{11}+4\frac{3}{9}=\frac{5}{11}+\frac{36+3}{9}=\frac{5}{11}+\frac{39}{9}$

$\displaystyle =\frac{5\times 9+11\times 39}{9\times 11}=\frac{45+429}{99}=\frac{474}{99}=\frac{158}{33}$

Simplify: $\dfrac{7\sqrt{3}}{\sqrt{10} + \sqrt{3}} - \dfrac{2\sqrt{5}}{\sqrt{6} + \sqrt{5}} -\dfrac{3\sqrt{2}}{\sqrt{15} + 3\sqrt{2}}$

  1. $0$

  2. $1$

  3. $2$

  4. $3$


Correct Option: B
Explanation:

$\dfrac{7\sqrt{3}}{\sqrt{10} + \sqrt{3}} - \dfrac{2\sqrt{5}}{\sqrt{6} + \sqrt{5}} -\dfrac{3\sqrt{2}}{\sqrt{15} + 3\sqrt{2}}\=\dfrac{7\sqrt{3}(\sqrt{10} - \sqrt{3})}{(\sqrt{10} + \sqrt{3})(\sqrt{10} - \sqrt{3})} - \dfrac{2\sqrt{5}(\sqrt{6} - \sqrt{5})}{(\sqrt{6} + \sqrt{5})(\sqrt{6} - \sqrt{5})} -\dfrac{3\sqrt{2}(\sqrt{15} - 3\sqrt{2})}{(\sqrt{15} - 3\sqrt{2})(\sqrt{15} + 3\sqrt{2})}\=\dfrac{7\sqrt{3}(\sqrt{10} - \sqrt{3})}{10-3} - \dfrac{2\sqrt{5}(\sqrt{6} - \sqrt{5})}{6-5} -\dfrac{3\sqrt{2}(\sqrt{15} - 3\sqrt{2})}{15-18}\=\dfrac{7\sqrt{3}(\sqrt{10} - \sqrt{3})}{7} - \dfrac{2\sqrt{5}(\sqrt{6} - \sqrt{5})}{1} +\dfrac{3\sqrt{2}(\sqrt{15} - 3\sqrt{2})}{3}$

$=\dfrac{21\sqrt{30}-63-425\sqrt{30}+210+21\sqrt{30}-18*7}{21}\=\dfrac{21}{21}=1$

Simplify:
$\dfrac{\sqrt{3} + \sqrt{2}}{\sqrt{3} - \sqrt{2}} + \dfrac{\sqrt{3} - \sqrt{2}}{\sqrt{3} + \sqrt{2}}$

  1. $4\sqrt{6}$

  2. $10$

  3. $2$

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


Correct Option: B
Explanation:

$\dfrac{\sqrt{3} + \sqrt{2}}{\sqrt{3} - \sqrt{2}} + \dfrac{\sqrt{3} - \sqrt{2}}{\sqrt{3} + \sqrt{2}}=\dfrac{(\sqrt{3} + \sqrt{2})^2+(\sqrt{3} - \sqrt{2})^2}{3-2}=\dfrac{3+2+3+2}{1}=10$

Reduce the following fractions to their lowest forms.
a. $\dfrac{36}{144}$


b. $\dfrac{65}{117}$

c. $\dfrac{180}{120}$

  1. $a=\dfrac{1}{4}, b=\dfrac{65}{117}, c=\dfrac{2}{3}$

  2. $a=\dfrac{1}{4}, b=\dfrac{5}{9}, c=\dfrac{3}{2}$

  3. $a=\dfrac{1}{4}, b=\dfrac{65}{117}, c=\dfrac{3}{2}$

  4. $a=\dfrac{3}{4}, b=\dfrac{65}{117}, c=\dfrac{2}{3}$


Correct Option: B
Explanation:

$\\(a.)(\frac{36}{144})=(\frac{3}{12})=(\frac{1}{4})\\(b.)(\frac{65}{117})=(\frac{13\cdot 5}{13\cdot 9})=(\frac{5}{9})\\(c.)(\frac{180}{120})=(\frac{60\cdot 3}{60\cdot 2})=(\frac{3}{2})$

The Simplified form of $0.35$ is

  1. $\dfrac {7}{20}$

  2. $\dfrac {4}{20}$

  3. $\dfrac {35}{100 }$

  4. $None$


Correct Option: A
Explanation:

$0.35$

$=\dfrac{35}{100}=\dfrac{7}{20}$

Given that  $n$  $AM's$  are inserted between two sets of numbers  $a , 2 b$  and  $2 a , b$  where  $a , b \in R .$  Suppose further that  $mth$  mean between these sets of numbers is same, then the ratio  $a : b$  is equal to

  1. $( n - m + 1 ) : m$

  2. $( n - m + 1 ) : n$

  3. $n : ( n - m + 1 )$

  4. $m : ( n - m + 1 )$


Correct Option: D
Explanation:

Let the common difference be d. As there are $n\;AM's$ between $a$ and $b$ and total number of terms in the sequence is $=n+2$ 

$\Rightarrow nth \;term\;b=a+\left( n-1\right)d$
      $d=\dfrac{\left( b-a\right)}{n+1}$
so, 2nd term that is first term $A\left( 1\right) =a+\left[ \dfrac{\left( b-a\right)}{\left( n+1\right)}\right]$
3rd term that is second mean $A\left(2\right)=a+\left[ 2\times \dfrac{ \left( b-a\right)}{\left( n+1\right)}\right]$
In the way $r^{th}$ mean $=a+\left[ r\times \dfrac{ \left( b-a\right) }{\left(n+1\right)}\right]$
In the first sequence first term is a $n^{th}$ term $=2b$ and $n\;AM's$ between them. 
As such from above concept  -
$\Rightarrow r^{th}$ term is $a+\left[ r\times \dfrac{\left( 2b-a\right)}{\left( n+1\right)}\right]$
       $m^{th}$ term is $a+\left[ m\times \dfrac{\left( 2b-a\right)}{\left( n+1\right)}\right]$
$ii)$ Similarly for second sequence -
    $m^{th}$ mean $=2a+\left[ m\times \dfrac{\left( b-2a\right)}{\left( n+1\right)}\right]$
$iii).$ Since the $m^{th}$ mean, are equal equation like the above. 
$=a+\left[ m\times \dfrac{\left( 2b-a\right)}{\left( n+1\right)}\right]$
$=2a+m\times \dfrac{\left( b-a\right) }{\left( n+1\right)}$
$=\left[ m\times \dfrac{\left( 2b-a\right)}{\left( n+1\right)}\right]-\left[ m\times \dfrac{\left( b-2a\right)}{\left( n+1\right)}\right]$
$=2a-a$
$\Rightarrow \dfrac{m}{\left( n+1\right)} \times \left( 2b-a-b+2a\right)=a$
$\dfrac{a+b}{a}=\dfrac{n+1}{m}$
subtracting on both sides 
$\Rightarrow \dfrac{a+b}{a}-1=\dfrac{n+1}{m}-1$
$\Rightarrow \dfrac{a+b-a}{a}=\dfrac{n+1-m}{m}$

$\Rightarrow \dfrac{b}{a}=\dfrac{n+1-m}{m}$

$\Rightarrow \dfrac {a}{b}=\dfrac{m}{n-m+1}$
Hence, the answer is $\dfrac{m}{n-m+1}.$

The lowest form of $3.5$ is 

  1. $\frac{7}{20}$

  2. $\frac{4}{20}$

  3. $\frac{35}{100}$

  4. $None$


Correct Option: A

Express in simpest from

  1. $-247/228$

  2. $-68/119$

  3. $87/116$

  4. $299/161$


Correct Option: B

If $\displaystyle\,5\,\dfrac{7}{x}\,\times\,y\,\dfrac{1}{13}\,=\,12$, where fractions are in their lowest terms, then $x - y$ is equal to 

  1. $2$

  2. $4$

  3. $7$

  4. $9$


Correct Option: C
Explanation:

$\displaystyle 5\,\frac{7}{x}\,\times\,y\,\frac{1}{13}\,=\,12$
By Hit and Trial method. 
Let $x = 9, y = 2$
Where the fractions are in their lowest terms, then x should be maximum possible single digit and $y$ is minimum possible single digit.
Putting this value in equ. (1)
$\displaystyle \,5\,\times\,\frac{7}{9}\,\times\,2\,\times\,\frac{1}{13}\,=\,\frac{52}{9}\,\times\,\frac{27}{13}\,=\,12
$
$\therefore \,x\,-\,y\,=7$
Hence, option 'C' is correct.

Simplest form of the ratio 140 : 24 is__

  1. 1 : 3

  2. 70 :12

  3. 6 : 35

  4. 35 : 6


Correct Option: D
Explanation:

We have, $ 140:24 $
Dividing by $ 4 $ we get $ 35:6 $
As there is no other common factor  to divide with, so $ 35:6 $ is the simplest form.

What is the reciprocal of $-3$?

  1. $-3$

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

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

  4. $3$

  5. Undefined


Correct Option: B
Explanation:

Reciprocal of $ -3 = \dfrac {1}{-3} $ or $ \dfrac {-1}{3} $

The value of $\left[\left(-2\displaystyle\frac{3}{4}\right)-\left(\displaystyle -1\frac{3}{4}\right)\right]+\left[\left(\displaystyle -2\frac{3}{4}\right)-\left(\displaystyle -1\frac{3}{4}\right)\right]+......$ upto $30$ times is:

  1. $-1$

  2. $1$

  3. $30$

  4. $-30$


Correct Option: D
Explanation:
Consider the given expression.

$\left [ \left ( -2\dfrac{3}{4} \right )- \left ( -1\dfrac{3}{4} \right )\right ]+\left [ \left ( -2\dfrac{3}{4} \right )- \left ( -1\dfrac{3}{4} \right )\right ]+.......$ upto $30$ times

Sum $=\left[\left(\dfrac{-11}{4}\right)-\left(\dfrac{-7}{4}\right)\right]+\left[\left(\dfrac{-11}{4}\right)-\left(\dfrac{-7}{4}\right)\right]+......$ upto $30$ times

        $=[-1]+[-1]+......upto\ 30\ times$

        $=-30$

Hence, the value of the expression is $-30$. 

The number $2.525252$ can be written as a fraction, when reduced to the lowest term, the sum of the numerator and denominator is:

  1. $7$

  2. $29$

  3. $141$

  4. $349$


Correct Option: D
Explanation:
Let the given number be $x=2.525252....$
multiplying with $100$ on both sides
$\Rightarrow 100x=252.525252...$
$\Rightarrow 100x=250+2.5252...$
$\Rightarrow 100x=250+x\Rightarrow 99x=250$
$\Rightarrow x=\dfrac{250}{99}$
$\therefore$ Sum of numerator and denominator $=25099=349$

The fraction $\dfrac {a^{2} + b^{2} - c^{2} + 2ab}{a^{2} + c^{2} - b^{2} + 2ac}$ is (with suitable restrictions on the values of $a, b,$ and $c$).

  1. Irreducible

  2. Reducible to $-1$

  3. Reducible to a polynomial of three terms

  4. Reducible to $\dfrac {a - b + c}{a + b - c}$

  5. Reducible to $\dfrac {a + b - c}{a - b + c}$


Correct Option: E
Explanation:

$\dfrac {a^{2} + b^{2} - c^{2} + 2ab}{a^{2} + c^{2} - b^{2} + 2ac} = \dfrac {(a + b)^{2} - c^{2}}{(a + c)^{2} - b^{2}} = \dfrac {(a + b + c)(a + b - c)}{(a + c + b)(a + c - b)}$
$= \dfrac {a + b - c}{a + c - b}$ with $(a + c)^{2} \neq b^{2}$.

The simplest rationalizing factor of $\sqrt{75}$ is.

  1. $(75)^{1/3}$

  2. $5\sqrt3$

  3. $3$

  4. $\sqrt{150}$


Correct Option: B
Explanation:

Let us first factorize $75$ as shown below:


$75=3\times 5\times 5=3\times { 5 }^{ 2 }$

Now consider $\sqrt {75}$ as follows:

$\sqrt { 75 } =\sqrt { 3\times 5\times 5 } =\sqrt { 3\times { 5 }^{ 2 } } =\sqrt { 3 } \times \sqrt { { 5 }^{ 2 } } =5\sqrt { 3 }$

Hence, the simplest rationalizing factor of $\sqrt {75}$ is $5\sqrt { 3 }$.

- Hide questions