uptetd16p1 q108
0. If 31x5 is a multiple of 9, where x is a digit, then the value of x will be
- Option : D
- Explanation : (D) By divisibility test, when the sum of all the digits of a number is divisible by 9, then the number is also divisible by 9.
Thus 31x5 is a multiple of 9 only when the sum of all the digits of a number is divisible by 9
∴ 3 + 1 + x + 5 = 9 + x
Hence, from the following given options, value of x - 9
9 + x = 9 + 9 = 18
and 18 is divisible by 9
∴ 195 is a multiple of 9 and x = 9
