Question

If 31x4 is a multiple of 3 where x is digit, what might be the value of x?​

Answer 1

Step-by-step explanation:

3 1 _ 4

There is simple technique to solve like these problems.

That is :

3 + 1 + 4 = 8

8 is not divisible by 3

If we add 1 in the place of x

That is 3 1 1 4

3114 is divisible by 3

3114 ÷ 3 = 1038

∴ value of x is 1

This simple technique applies to all, excluding for the multiples of 5 and 10.

For the multiples of 5, the last digit of the number should be 5 or 0.

For the multiples of 10, the last digit of the number should be 0.