If a nine-digit number 385x3678y is divisible by 72, then the value of (y-x) is:
Show answer & explanation
Correct answer: C
Explanation
The correct answer is option 3 i.e. 3.
Divisibility by 8 → Last 3 digits 78y
784 ÷ 8 = 98 ⇒ y = 4
Divisibility by 9 → Sum of digits = 3 + 8 + 5 + x + 3 + 6 + 7 + 8 + 4 = 44 + x
For divisibility by 9: 44 + x = 45 ⇒ x = 1
y − x = 4 − 1 = 3