Question

The number X4531Y, where X and Y are single-digit numbers, is divisible by 72. Then X - Y is equal to

• A. 5
• B. 7
• C. 8
• D. 4
• E. 1

Answer 1

The correct option is D 4

If a number is divisible by 72, it is divisible by 8 and 9. To be divisible by 8, the number formed by the last three digits should be divisible by 8. Therefore, 31Y should be divisible by 8=> Y = 2. To be divisible by 9, the sum of the digits of the number should be divisible by 9=> X = 3. Therefore, X-Y = 1