2005 AMC 12B Problems/Problem 2: Difference between revisions

Revision as of 21:08, 17 April 2009

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

$\mathrm{(A)}\ 2 \qquad \mathrm{(B)}\ 4 \qquad \mathrm{(C)}\ 10 \qquad \mathrm{(D)}\ 20 \qquad \mathrm{(E)}\ 40$

$2x+7=3 \Rightarrow 2x = -4 \Rightarrow x = -2$ .

$-2b-10=-2 \Rightarrow -2b = 8 \Rightarrow b = \boxed{-4}$ .

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 == Problem ==
-The equations <math>2x+7=3</math> and <math>bx-10=-2</math> have the same solution for <math>x</math>.  What is the value of <math>b</math>?
+A positive number <math>x</math> has the property that <math>x\%</math> of <math>x</math> is <math>4</math>.  What is <math>x</math>?
 <math>
-\mathrm{(A)}\ -8      \qquad
+\mathrm{(A)}\ 2      \qquad
-\mathrm{(B)}\ -4      \qquad
+\mathrm{(B)}\ 4      \qquad
-\mathrm{(C)}\ -2      \qquad
+\mathrm{(C)}\ 10      \qquad
-\mathrm{(D)}\  4      \qquad
+\mathrm{(D)}\ 20      \qquad
-\mathrm{(E)}\  8
+\mathrm{(E)}\ 40
 </math>