Very tricky problem, thinking answers may help me!?

Question

Which variables can equal zero if it is true that:
(w/x) divided by (y/z) = (WZ)/(XY)

Answer 1

Variables can NOT be zero if they are in the denominator of a fraction. The divisors in your problem are x, z, (y/z) and (xy).

x cannot be 0
z cannot be 0
(y/z) cannot be 0 --> y cannot be 0
(xy) cannot be 0 ---> neither x nor y can be 0

The only variable left, which can be 0, is W.

Answer 2

Well, you can't divide by zero (it's undefined) so w can equal zero so the result would be:
0/x all over y/z, 0/x = 0 and 0 over y/z equals zero. Making w = 0 puts a 0 on the right side, too. I guess that's valid.