For what value of digit x is :

1x5 divisible by 3 ?

According to the divisibility of 3, if the sum of the digits of the number is divisible by 3 then the number is divisible by 3.

1x5 = 1 + x + 5 = 6 + x. And (6 + x) should be a multiple of 3.

Hence, 6 + x = 0 ,3, 6, 9, 12, 15, 18, ……

x = -6, -3, 0, 3, 6, 9, 12,…..

Since, x is a digit. ∴ x = 0, 3, 6 or 9