2001 AMC 12 Problem 3

Below is the professionally curated solution for Problem 3 of the 2001 AMC 12, from LIVE by Po-Shen Loh. You can also try the full timed exam, view all 2001 AMC 12 solutions, or check the answer key.

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Concepts:percentagelinear equation

Difficulty rating: 1240

3.

The state income tax where Kristin lives is levied at the rate of p%p\% of the first $28000\$28000 of annual income plus (p+2)%(p + 2)\% of any amount above $28000.\$28000. Kristin noticed that the state income tax she paid amounted to (p+0.25)%(p + 0.25)\% of her annual income. What was her annual income?

$28000\$28000

$32000\$32000

$35000\$35000

$42000\$42000

$56000\$56000

Solution:

Let her income be x>28000x \gt 28000 dollars. Writing the tax with both descriptions and multiplying by 100,100, p28000+(p+2)(x28000)=(p+0.25)x. p \cdot 28000 + (p + 2)(x - 28000) = (p + 0.25)x.

Expanding, every term containing pp cancels, leaving 2x56000=0.25x, 2x - 56000 = 0.25x, so 1.75x=560001.75x = 56000 and x=32000.x = 32000.

Thus, the correct answer is B.

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