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2001 AMC 12 Problem 3

Problem 3 of 25EasierAlgebra

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?

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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. \begin{aligned} &p \cdot 28000 \\ &\quad {}+ (p + 2)(x - 28000) \\ &= (p + 0.25)x. \end{aligned} 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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Concepts: percentage · linear equation

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