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PCAT Quantitative Reasoning – Composite Functions

  • by Sam
  • Apr 19, 2018
  • PCAT Question of the Day

If  f(x) = x3/8 – 1, which of the following expressions for g(x) would satisfy g(f(4))=24?

A. g(x) = 3x + 3
B. g(x) = 5x – 6
C. g(x) = 6x
D. g(x) = 7x

Click for Explanation

A is correct. To evaluate this composite function, let’s plug x = 4 into f(4):

Therefore, g(7) = 24. The only answer choice that satisfies this relationship is Choice A:

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