Official Guide Explanation:
Problem Solving #D12




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Solution and Metadata

Question: D12
Page: 22
Difficulty: 5 (Moderate)
Category 1: Arithmetic > Percents > other
Category 2: Algebra > Linear Equations-Two Unk >

Explanation: The question gives us two equations. First:

y = (1/2)((1/2))(x)


((y)/100)(x) = 100 ("y percent" is the same as ((y)/100))

Simplifying them:

y = (1/4)x

xy = 10,000

Substitute the first into the second:

x((1/4)x) = 10,000

x2 = 40,000

x = 200, choice (C).

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