A number consists of two digits. If the digits interchange places and the new number is added to the original number, then the resulting number will be divisible by:

• A. 11
• B. 5
• C. 3
• D. 9

Answer: (A)

Let the ten's digit be x and unit's digit be y. Then, number 10x + y.Number obtained by interchanging the digits = 10y + x.(10x + y) + (10y + x) = 11(x + y)which is divisible by 11.