Joe P.

asked • 08/21/19

SAT Math 2 -- Question involving Functions

Please help me understand the following question--


If f(2x) = x+5 and f(g(6)) = 13, then 2 * (g(6)) equals


A) 6

B) 16

C) 32

D) 36

E) 64

2 Answers By Expert Tutors

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Richard P. answered • 08/21/19

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Since f(2x) = x + 5 , then f(x) = x/2 + 5


f( g(6) ) = 13 implies that g(6) /2 + 5 = 13 , so g(6) = 32

Which is choice C

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Joe P.

Thank you very much!
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08/21/19

Stephen C.

I agree with you right up until "g(6) = 32" ... which should be "g(6) = 16", right? But we're actually asked for 2*g(6), which is 32, and (still) choice C.
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08/21/19

Brian P.

I agree with joe-- Correct
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08/29/19

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