Q.
If 24x is a
multiple of 3, where x is a digit, what is the value of x?
(Since 24x is a
multiple of 3, its sum of digits 6 + x is a multiple of 3; so
6 + x is one of these numbers: 0, 3, 6, 9, 12, 15, 18….
But since x is a digit, it can only be that 6 + x = 6
or 9 or 12 or 15. Therefore, x = 0 or 3 or 6 or 9. Thus, x
can have any of four different values)