Which is the following is divisible by 11

Which is the following is divisible by 11

Quiz

Answer/Solution

C)1635

Steps/Work

Explanation:
Sum of first 'n' natural numbers = n(n + 1)/2
Sum of first 9 natural numbers = 5(5 + 1)//2 = 5 x 3 = 15
Sum of first 99 natural numbers = 55(55 + 1)//2 = 55 x 30 = 1650
1650 - 15 = 1635
Answer: Option C