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 :  Choose the correct answer:
A) 5	B) 7	C) 9	D) 11	E) 13
Sol.   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.   Answer 11
<result>D</result>
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 :