1951 AMC 12 Problem 5

Attempt Problem 5 of the 1951 AMC 12 below, then check your answer against the professionally curated solution from LIVE by Po-Shen Loh. You can also try the full timed exam, view all 1951 AMC 12 solutions, or check the answer key.

All problems are used with official legal permission of the Mathematical Association of America (MAA).

5.

Mr. AA owns a home worth $10,000.\$10{,}000. He sells it to Mr. BB at a 10%10\% profit based on the worth of the house. Mr. BB sells the house back to Mr. AA at a 10%10\% loss. Then:
AA comes out even
AA makes $1100\$1100 on the deal
AA makes $1000\$1000 on the deal
AA loses $900\$900 on the deal
AA loses $1000\$1000 on the deal
Answer: B
Concepts:percentagemoney
Small hint:
Compute the two sale prices separately
Big hint:
The first sale is for 10,000(1.10)10{,}000(1.10), and the return sale is 10%10\% below that amount
Solution:
The first sale price is 10,000(1.10)=11,000.10{,}000(1.10)=11{,}000. The return sale is 11,000(0.90)=9,900.11{,}000(0.90)=9{,}900. Mr. AA receives 11,00011{,}000 and pays back 9,900,9{,}900, so he gains 1,100.1{,}100.
Thus, the correct answer is B.
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