Question

Find all possible values of x for which the 4-digit number 320x is divisible by 3. Also, find the numbers.

Answer 1

We know that if sum of digits of a number is divisible by 3, then the number is divisible by 3.

Here,

3 + 2 + 0 + x = multiple of 3

5 + x = 0, 3, 6, 9, 12, 15, ….

Hence,

1) 5 + x = 6

∴ x = 1

2) 5 + x = 9

∴ x = 4

3) 5 + x = 12

∴ x = 7

Hence, possible number 3201, 3204 and 3207.