Solutions
Since 88 = 8 × 11
The number must be divisible by 8 and 11 individually
First, rule of divisibility by 8:
Last three digits of the number must be divisible by 8.
Therefore, the last three digits (10x) of the number will be 104. (no other digit will make it divisible by 8)
Therefore, x = 4.
Now, rule of divisibility by 11:
Difference between sum of digits at odd place and sum of digits at even place must be divisible by 11.
Therefore,
(2 + 6 + 1 + 4) – (y + 8 + 0) = 11n, where n is any integer
⇒ 13 – (y + 8) = 11n
⇒ –y + 5 = 11n
⇒ –y + 5 = 0 (n = 0, because n = 1 will make ‘y’ negative and -1 will make ‘y’ a double digit number)
Therefore, y = 5.
Now, (x) × (y) = 4 × 5 = 20