Solution:
Concept:
The divisibility rule of 8 states that for a number to be divisible by 8, its last three-digit should be perfectly divisible by 8.
The divisibility rule of 11 states that for a number to be divisible by 11, the difference between the sum of odd and even digits should be completely divisible by 11.
Calculations:
Using Divisibility rule of 8, we get-
∴ 4y2 is completely divisible by 8 if y is 7(largest value of y). (∴ y = 7)
Similarly using divisibility rule of 11, we get-
⇒ (7 + 6 + 4 + 2) - (x + 3 + 7) = 19 - 10 - x = 9 - x
⇒ The number is perfectly divisible if x = 9 (∴ x = 9)
∴ Value of x - y = 9 - 7 = 2
The value of x - y is 2.
