Correct Answer - Option 2 : 20
Given:
n = 475AB
Concept:
Divisibility test 5 = Numbers, which last with digits, 0 or 5 are always divisible by 5.
Divisibility test 8 = If the last three digits of a number are divisible by 8, then the number is completely divisible by 8.
Divisibility test 9 = If the sum of digits of the number is divisible by 9, then the number itself is divisible by 9.
Calculation:
For 5, A = 2 and B = 0 then number is divisible by 5.
But when last three digit is 520, number is divisible by 8.
For 9: 4 + 7 + 5 + A + B = 16 + A + B, then to be divisible by 9, A + B must be 2.
We can not take A + B = 11 as then number is not divisible by 5.
Then A = 2 and B = 0
∴ 10A + B = 10 × 2 + 0 = 20