Is the number x is divisible by 9?
A: The number x can be obtained by taking the difference between a number and another one obtained by reversing the digits.
B: The sum of the digits of x is divisible by 9
My answer was B but OA was A
A. let a & b be the digits, then 10a+b is one number, and 10b+ a is the revesred number the difference = 9a - 9b = 9(a-b)
Always divisible by 9.
I am not sure why B is wrong though, B may be wrong because we don't know whether x is integer.