Is yz = x? (1) y > x/z (2) z < 0

1) y >x/z
this gives yz>x , when z +ve , or yz<x , when z -ve. Thus yz is not equal, no matter what z is. SUFF
2) z<0 . now in yz = x, with z <0 but no other info about y or x, we cannot say whether yz = x, yz<x or yz>x. clearly NS.

Ans A.

VERITAS PREP OFFICIAL SOLUTION:

You actually don’t need to know the sign. When you use statement 1 alone and multiply both sides by z, you either get yz > x (if z is positive) or yz < x (if z is negative). It’s either greater than or less than with no room for equals, so you don’t need the sign. So statement 2 isn’t always necessary, but if it appears to give assistance you’ve got to look – you have to at least consider whether it’s important, because that’s where the GMAT has set up the difficulty. On the most difficult problems, the GMAT will tend to reward those who can leverage all available information to think critically and make a good decision, so it pays to at least take a fairly-obvious-on-its-own statement and look at it in the context of the other statement, just in case.

Answer: A.

[quote="Bunuel"]Is yz = x?

(1) y > x/z
(2) z < 0


The question asks if yz=x => y=x/z .
(1) first statement tells us that y is strictly greater than x/z, that means y not equals x/z. Answer is no . Sufficient.
(2) statement 2 says z is negative, since we do not have any other information, the answer might be yes or no. Insufficient.
Hence, Answer is A.

Solved that in 5 seconds. It was very easy.

For yz to be equal to x, y has to be equal to x/z which statement 1 negates.

Statement 2 does not have enough information.

The answer is A.

Asked: Is yz = x?

(1) y > x/z
y-x/z > 0
yz is NOT = z
SUFFICIENT

(2) z < 0
Since y & x are unknown
NOT SUFFICIENT

IMO A

Is yz = x?

(1) y > x/z

If z > 0, then we'd get yz > x.
If z < 0, then we'd get yz < x.

In any case yz = x is not possible.

Sufficient.

(2) z < 0. Clearly insufficient.

Answer: A.