2008 AMC 12A Problem 3

Below is the professionally curated solution for Problem 3 of the 2008 AMC 12A, from LIVE by Po-Shen Loh. You can also try the full timed exam, view all 2008 AMC 12A solutions, or check the answer key.

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Concepts:ratio and proportion

Difficulty rating: 1100

3.

Suppose that 23\tfrac{2}{3} of 1010 bananas are worth as much as 88 oranges. How many oranges are worth as much as 12\tfrac{1}{2} of 55 bananas?

22

52\dfrac{5}{2}

33

72\dfrac{7}{2}

44

Solution:

Since 23\tfrac{2}{3} of 1010 bananas is 203\tfrac{20}{3} bananas, worth 88 oranges, one banana is worth 8÷203=2420=65 8 \div \dfrac{20}{3} = \dfrac{24}{20} = \dfrac{6}{5} oranges.

Then 12\tfrac{1}{2} of 55 bananas is 52\tfrac{5}{2} bananas, worth 5265=3 \dfrac{5}{2} \cdot \dfrac{6}{5} = 3 oranges.

Thus, C is the correct answer.

Problem 3 in Other Years