Question

Find all possible values of y for which the 4-digit number 64y3 is divisible by 9. Also, find the numbers.

Answer 1

We know that if sum of digits of a number is divisible by 9, then the number is divisible by 9. 

Here, 

6 + 4 + y + 3 = multiple of 9 

y + 13= 0, 9, 18, … 

Hence, 

y + 13 = 18 

∴ y = 5 

The number will be 6453.