Lesson: Exponential Growth

Comment on Exponential Growth

Hi - regarding the below question from
GMAT practice question (difficulty level: 500 to 650) - Math Revolution

Which of the following is closest to (-3/4)^199?
A. -1
B. -1/2
C. 0
D. 1
E. 2

You guys say the OA is C... I understand that as the fraction's exponent increases, the magnitude will decrease and continue approaching zero. But given that the exponent is odd shouldn't the answer be B?
gmat-admin's picture

You're right in that the odd exponent means (-3/4)^199 equals some negative number. However that negative number is very close to 0.

Using a scientific calculator (which isn't provided on test day) we can calculate this.

We get: (-3/4)^199 ≈ -0.000000000000000000000000137

As you can see, this number if a lot closer to 0 than it is to -1/2

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