M7MBA wrote: ↑Sun Apr 25, 2021 2:56 pm
Is \(w+h^4\) positive?
(1) \(h\) is positive
(2) \(w\) is positive
Answer:
B
Source: Official Guide
Target question: Is w + h^4 positive?
Statement 1: h is positive
Let's TEST some values.
There are several values of w and h that satisfy statement 1. Here are two:
Case a: w = 1 and h = 1. In this case,
w + h^4 = 1 + 1^4 = 2. So, w + h^4 IS positive
Case b: w = -3 and h = 1. In this case,
w + h^4= -3 + 1^4 = -2. So, w + h^4 is NOT positive
Since we cannot answer the
target question with certainty, statement 1 is NOT SUFFICIENT
Statement 2: w is positive
Important concept: (any number)^(even integer) =
a value greater than or equal to 0
Statement 2 tells us that w is
some positive number
We can write:
w +
h^4 = (
some positive number) + (
a value greater than or equal to 0)
We can see that
w + h^4 positive is definitely positive
Since we can answer the
target question with certainty, statement 2 is SUFFICIENT
Answer: B
Cheers,
Brent
Brent Hanneson - Creator of GMATPrepNow.com
