Explanation

The question stem tells us that either x must be 0 or else y must equal z.

Statement (1) We cannot determine whether z = 2 or x = 0 AND z = 4, so this statement alone is insufficient.

The correct answer could be B, C, or E. Statement (2) Since , y must equal z. But without knowing the value of y, we do not know whether.

The correct answer must be either C or E. Statement (1 & 2) The statements together tell us , so they are sufficient together.

**The correct choice is C.**

Statement (1) We cannot determine whether z = 2 or x = 0 AND z = 4, so this statement alone is insufficient.

The correct answer could be B, C, or E. Statement (2) Since , y must equal z. But without knowing the value of y, we do not know whether.

The correct answer must be either C or E. Statement (1 & 2) The statements together tell us , so they are sufficient together.

## 3 Comments

this is a messed up explanation, even the vocab is not good.

What if:

xy=xz then, xy-xz=0 x(y-z)=0 x=0; y-z=0; y=z

choice A says that y=2; then z is also 2, this should be sufficient to answer that z is not 4, but 2

Please clarify.

@Emil - for x=0, y not necessarily equals to z, hence without knowing about whether x is 0 or not we can not come to any conclusion.