Bunuel
If each of w, x, y and z are positive numbers, is \(\frac{w}{x}*\frac{y}{z} > \frac{y}{x}\) ?
(1) y > x
(2) w > z
Given: w, x, y and z are positive numbers, Target question: Is \((\frac{w}{x})(\frac{y}{z}) > \frac{y}{x}\)?This is a good candidate for
rephrasing the target question Take:
\((\frac{w}{x})(\frac{y}{z}) > \frac{y}{x}\)Simplify:
\(\frac{wy}{xz} > \frac{y}{x}\)Since \(x\) is POSITIVE, we can safely multiply both sides of the inequality by \(x\) to get:
\(\frac{wy}{z} > y\)Likewise, since \(z\) is POSITIVE, we can multiply both sides \(z\) to get:
\(wy > yz\)Finally, since \(y\) is POSITIVE, we can divide both sides \(y\) to get:
\(w > z\)REPHRASED target question: Is \( w> z\) ?Aside: the video below has tips on rephrasing the target question Statement 1: y > x Since statement 1 provides no information about w and z, there is no way to answer the
REPHRASED target question with certainty.
So, statement 1 is NOT SUFFICIENT
Statement 2: w > zPerfect! The answer to the REPHRASED target question is
YES, w is greater than zSince we can answer the
target question with certainty, statement 2 is SUFFICIENT
Answer: B
Cheers,
Brent
RELATED VIDEOS