[quote="Bunuel"]
The Official Guide For GMAT® Quantitative Review, 2ND EditionOn 3 sales John has received commissions of $240, $80, and $110, and he has 1 additional sale pending. If John is to receive an average (arithmetic mean) commission of exactly $150 on the 4 sales, then the 4th commission must be
(A) $164
(B) $170
(C) $175
(D) $182
(E) $185
Problem Solving
Question: 32
Category: Arithmetic Statistics
Page: 66
Difficulty: 600
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[/quote)
(140+50+240+x)/(4)=150
600=430+x
x=170