Tag: negative numbers and integers

Questions Related to negative numbers and integers

If the number of consecutive odd integers whose sum can be expressed as $50^2 - 13^2$ is k then k, can be 

  1. 33

  2. 35

  3. 37

  4. 39


Correct Option: C
Explanation:

Sum of odd $n$ consecutive numbers $n^2$

$\therefore (1+3+5\dots\dots (2n-1))=n^2$
where $n$ represents the number of terms.
$\therefore 50^2=1+3+5\dots 99=50\text{ }terms$
$\therefore 13^2=1+3+5\dots 25=13\text{ }terms$
$\therefore 50^2-13^2$$=(1+3+5\dots 99)-(1+3+5\dots 25)\=(27+29\dots 99)\ =37\text{ }terms.$

The general form of an even number is 

  1. $2n-1$

  2. $2n$

  3. $2n+1$

  4. $2$


Correct Option: B
Explanation:

An even number is a number which has a factor of $2$.

Therefore, general term will be $2n$

Odd numbers are not divisible by

  1. one

  2. two

  3. odd numbers

  4. negative integers


Correct Option: B
Explanation:

Odd numbers are not divisible by $2$

Difference between two even numbers after and before $2n$, where $n$ is a positive number, is-

  1. $0$

  2. $4$

  3. $2$

  4. $6$


Correct Option: B
Explanation:
Even number after $2n=2n+2$
Even number before $2n=2n-2$
Difference$=2n+2-\left(2n-2\right)=4$

Pick out even number:
$123, 246, 145, 279$

  1. $123$

  2. $ 246$

  3. $ 145$

  4. $279$


Correct Option: B
Explanation:

A number is even if the digit in One's place is divisible by $2$.


Out of the numbers $123,246,145,279$ only $246$ is even as it has $6$ at unit's place which is divisible by $2$.

The sum of even numbers between $1$ and $31$ is:

  1. $6$

  2. $28$

  3. $240$

  4. $512$


Correct Option: C
Explanation:

Let ${S} _{n}=(2+4+6+.....+30)$. This is an A.P in which $a=2,d=2$ and $l=30$
Let the number of terms be $n$. Then,
$a+(n-1)d=30$
$\Rightarrow$ $2+(n-1)\times 2=30$
$\Rightarrow$ $n=15$
$\therefore$ ${S} _{n}=\cfrac{n}{2}(a+l)=\cfrac{15}{2}\times (2+30)=(15\times 16)=240$.

$-1$ is an odd integer, 5th consecutive integer is

  1. Odd

  2. Even

  3. Zero

  4. None


Correct Option: B
Explanation:

$-5,-4,-3,-2,-1,0,1,2,3,4,5$

This is set of integers in neighbourhood of $-1$ as per number line.
$5$th conescutive integer as seen from above, is $4$ which is Even.

Which one of the following is even?

  1. $9 \times 14$

  2. $15 \times 17$

  3. $17 \times 9 $

  4. $11 \times 19$


Correct Option: A
Explanation:

$9\times 14=9\times 2\times 7$

$\Rightarrow 9\times 14$ has $2$ as one of its factor.
So it is an even number
None of the other options has $2$ as their multiple
So option $A$ is correct.

Which of the following is positive even integer?

  1. $4$

  2. $-4$

  3. $0.3$

  4. $-2$


Correct Option: A
Explanation:

Out of the following the integer which is positive and even is 4. Thus, option A is correct.

Every even integer can be written as  
(Note:  $m$ is any integer)

  1. $m$

  2. $m + 1$

  3. $2m$

  4. $2m + 1$


Correct Option: C
Explanation:

Any even integer is divisible by $2$.

so we can write it as  $2m$