2005 AMC 10B Problem 2 — Solution | LIVE by Po-Shen Loh

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2005 AMC 10B Problem 2

Attempt Problem 2 of the 2005 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 2005 AMC 10B solutions, or check the answer key.

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

2.

A positive number $x$ has the property that $x\%$ of $x$ is $4.$ What is $x?$

$2$

$4$

$10$

$20$

$40$

Answer: D

Concepts:percentage quadratic

Difficulty rating: 880

Solution:

The statement translates to $\dfrac{x}{100}\cdot x = 4,$ so $x^2 = 400.$

Since $x$ is positive, $x = 20.$

Thus, D is the correct answer.

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Problem 2 in Other Years

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