BTGModeratorVI wrote: ↑Thu Aug 20, 2020 7:19 am
If xy < zy < 0, is y positive?
(1) x < z
(2) x is negative
Answer:
D
Source: Veritas Prep
Target question: Is y positive?
Given: xy < zy < 0,
Let's focus on this part of the inequality: xy < zy
Subtract xy from both sides to get: 0 < zy - xy
Factor out the y to get:
0 < y(z - x) (this will come in handy later)
Statement 1: x < z
Subtract x from both sides to get: 0 < z - x
In other words, (z - x) is POSITIVE
This means we can take our given inequality
0 < y(z - x) and divide both sides by (z - x) to get: 0 < y
So, the answer to the target question is
YES, y IS positive
Since we can answer the
target question with certainty, statement 1 is SUFFICIENT
Statement 2: x is negative
The given information tells us that xy < zy < 0
This means xy < 0
In other words, xy is NEGATIVE
So, if x is negative, then it MUST be the case that
y is POSITIVE
Since we can answer the
target question with certainty, statement 2 is SUFFICIENT
Answer: D
Cheers,
Brent
