Question

3a9 is divisible by 9 if the digit 'a' is equal to

• A. 2
• B. 4
• C. 6
• D. 8

Answer 1

The correct option is C

6

For the number to be divisible by 9 the sum of digits of number must be divisible by 9.
Sum of the digits of 3a9 = 3 + a + 9 = 12 + a

12 + a should be a multiple of 9 to satisfy the condition. The nearest multiple of 9 next to 12 is 18.

Therefore, 12 + a = 18

So, a = 18 - 12 = 6