AbdurRakib wrote:
Is \(w + h^4\) positive?
(1) h is positive
(2) w is positive
Target question: Is w + h⁴ 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 + h⁴ = 1 + 1⁴ = 2. So, w + h⁴ IS positiveCase b: w = -3 and h = 1. In this case,
w + h⁴ = -3 + 1⁴ = -2. So, w + h⁴ is NOT positiveSince 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 0Statement 2 tells us that w is
some positive numberWe can write:
w +
h⁴ = (
some positive number) + (
a value greater than or equal to 0)
We can see that
w + h⁴ positive is definitely positiveSince we can answer the
target question with certainty, statement 2 is SUFFICIENT
Answer: B
Cheers,
Brent
_________________
Brent Hanneson – Creator of gmatprepnow.com
I’ve spent the last 20 years helping students overcome their difficulties with GMAT math, and the biggest thing I’ve learned is…
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