Question

Which of the following is divisible by 37?

• A. ab + ba
• B. ab - ba
• C. abc - cba
• D. abc + bca + cab

Answer 1

The correct option is D abc + bca + cab

ab + ba is not divisible by 37.

For ex. 12 + 21 = 33 which is not divisible by 37.

ab - ba is not divisible by 37.

For ex. 21 - 12 = 9 which is not divisible by 37.

abc - cba = 100a + 10b+ c - 100 c - 10b - a
= 99a - 99 c = 99 (a -c), which is not divisible by 37.


abc + bca + cab = 100a + 10b + c + 100b + 10c + a + 100c + 10a + b
= 111(a+b+c) which is divisible by 37.