Which one of the following is a factor of the sum of first twenty-five natural numbers ?

A. 26

B. 24

C. 13

D. 12

Answer: Option C

Solution(By Examveda Team)

Sum first n natural numbers
$${\text{ = }}\left[ {\frac{{{\text{n(n + 1)}}}}{2}} \right] = 25 \times 13$$
Sum of first 25 natural numbers
$${\text{ = }}\frac{{25(26)}}{2} = 25 \times 13$$
Now check option
Clearly, we can see 13 is factor
So, '13' is answer