Question

If 31z5 is a multiple of 3, where z is a digit, what might be the values of z?

Answer 1

Since 31z5 is a multiple of 3.
Therefore according to the divisibility rule of 3, the sum of all the digits should be a multiple of 3.
Since, z is a digit.

Hence 0, 3, 6 and 9 are four possible answers.