2005 AMC 12B Problem 3

Attempt Problem 3 of the 2005 AMC 12B 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 2005 AMC 12B solutions, or check the answer key.

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3.

Brianna is using part of the money she earned on her weekend job to buy several equally-priced CDs. She used one fifth of her money to buy one third of the CDs. What fraction of her money will she have left after she buys all the CDs?

15\dfrac{1}{5}

13\dfrac{1}{3}

25\dfrac{2}{5}

23\dfrac{2}{3}

45\dfrac{4}{5}

Answer: C
Concepts:fractionratio and proportion
Difficulty rating: 1050
Solution:

Buying all the CDs costs three times what one third of them cost, namely 315=353\cdot\dfrac15 = \dfrac35 of her money.

She has 135=251 - \dfrac35 = \dfrac25 of her money left.

Thus, the correct answer is C.

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