2009 AMC 10B Problem 5 — Solution | LIVE by Po-Shen Loh

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2009 AMC 10B Problem 5

Attempt Problem 5 of the 2009 AMC 10B 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 2009 AMC 10B solutions, or check the answer key.

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

5.

Twenty percent less than $60$ is one-third more than what number?

$16$

$30$

$32$

$36$

$48$

Answer: D

Concepts:percentage linear equation

Difficulty rating: 870

Solution:

Twenty percent less than $60$ is $\dfrac45\cdot60=48.$

If $n$ is the unknown number, one-third more than $n$ is $\dfrac43 n,$ so $\dfrac43 n=48$ $n=36.$

Thus, the correct answer is D.

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