ABC26GN0292 · Number System

Subject: General Aptitude · Chapter: Number System · Exam: · Marks: · Difficulty:

The difference of a number consisting of two digits and the number formed by interchanging the digits is always divisible by

(a)5

(b)7

(c)9

(d)11

Answer

Answer (as printed): C

Explanation

Let the ten's digit be x and the unit's digit be y. Then, (10x + y) – (10y + x) = 9x – 9y = 9(x – y), which is divisible by 9.

Explanation as extracted from the printed page; notation may be imperfect.