Question

Find the sum of all the natural numbers between 1 to 100 which are divisible by 6.

• A. 816
• B. 812
• C. 814
• D. 820

Answer 1

The correct option is A 816

The numbers which are divisible by 6 are 6, 12, 18, 24,.... 96.
Sum of all the natural numbers are as follows:
6 + 12 + 18 + 24 +... + 96
= 6 (1 + 2 + 3 + 4 + .... + 16)

Now, applying the formula $\frac{n(n+1)}{2}$,
= 6 x $\frac{16(16+1)}{2}$
= 6 x $\frac{16\left(17\right)}{2}$
= 3 x 16 x 17
= 816