A nine – digit number 89563x87y is divisible by 72. What is the value of 
?
Options
a) 8
b) 5
c) 6
d) 4
Solution
As per question
89563x87y is divisible by 72
Factor of 72 = 9 x 8
The number will be divided by 9 and 8
Divisibility Rule
The number is divisible by 8 if last 3 digit are divisible by 8
Only possible number of y = 2
The number is divisible by 9 , if the sum of digits are divisible by 9
8 + 9 + 5 + 6 + 3 + x + 8 + 7 + 2
48 + x
The possible number after 48 divisible by 9 is 54
48 + x = 54
x = 54 – 48 = 6
Put the value of x and y:
Ans: 6