If 31 a5 is a multiple of 3,where a is a digit,what could be the values of a?

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

If 24x is a multiple of 3,where x is a digit,what is the value of x?

If 31z5 is a multiple of 9,where z is a digit,what is the value of z?You will find that there are two answers for the last problem.Why is this so?

If 21y5 is a multiple of 9,when y is a digit,what is the value of y?

n(n+1)(n+5) is a multiple 3.

If sin 3A = cos (A-10^(@)) where 3A is an acute angle, find the value of A.

Let A = {x : x is a multiple of 3} and B = {x : x is a multiple of 5), then A nn B is given by

If (x+1,1) = (3,1) find the value of 'x'?

What is the value of |3I_3| where I_3 is the identity matrix of order 3?