Official Guide Explanation:
Problem Solving #132




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Solution and Metadata

Question: 132
Page: 171
Difficulty: 4 (Moderately Easy)
Category 1: Algebra > Linear Equations-One Unk >
Category 2: Word Problems > Mixture Problems >
Category 3: Arithmetic > Descriptive Statistics > Average

Explanation: This is a classic weighted average problem. As usual, remember that the actual numbers don't matter: it's the difference between them that counts. So, instead of working with an average of $400 and a first - six - day revenue of $360, subtract $360 from everything, leaving an average of $40 and a first - six - day revenue of $0. Then, the equation looks like this: ((6(0) + 4(x))/10) = 40. Then: 4x = 400, and x = 100. Since we started by subtracting $360 from everything, we have to add that back, giving us 100 + 360 = 460, choice (D).

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