Difference between revisions of "2016 AMC 12A Problems/Problem 3"

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(Solution)
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==Solution==
 
==Solution==
 
<cmath>\text{rem}\left(\frac{3}{8},-\frac{2}{5}\right)</cmath>
 
<cmath>\text{rem}\left(\frac{3}{8},-\frac{2}{5}\right)</cmath>
<cmath>=\frac{3}{8}-\left(-\frac{2}{5}\right)\lfloor\frac{\frac{3}{8}}{-\frac{2}{5}}\rfloor</cmath>
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<cmath>=\frac{3}{8}-\left(-\frac{2}{5}\right)\Big\lfloor\frac{\frac{3}{8}}{-\frac{2}{5}}\Big\rfloor</cmath>
<cmath>=\frac{3}{8}+\left(\frac{2}{5}\right)\lfloor -\frac{15}{16}\rfloor</cmath>
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<cmath>=\frac{3}{8}+\left(\frac{2}{5}\right)\Big\lfloor -\frac{15}{16}\Big\rfloor</cmath>
 
<cmath>=\frac{3}{8}+\left(\frac{2}{5}\right)\left(-1\right)</cmath>
 
<cmath>=\frac{3}{8}+\left(\frac{2}{5}\right)\left(-1\right)</cmath>
 
<cmath>=\frac{3}{8}-\frac{2}{5}</cmath>
 
<cmath>=\frac{3}{8}-\frac{2}{5}</cmath>
 
<cmath>=\boxed{\textbf{(B)}-\frac{1}{40}}</cmath>
 
<cmath>=\boxed{\textbf{(B)}-\frac{1}{40}}</cmath>

Revision as of 22:40, 3 February 2016


Solution

\[\text{rem}\left(\frac{3}{8},-\frac{2}{5}\right)\] \[=\frac{3}{8}-\left(-\frac{2}{5}\right)\Big\lfloor\frac{\frac{3}{8}}{-\frac{2}{5}}\Big\rfloor\] \[=\frac{3}{8}+\left(\frac{2}{5}\right)\Big\lfloor -\frac{15}{16}\Big\rfloor\] \[=\frac{3}{8}+\left(\frac{2}{5}\right)\left(-1\right)\] \[=\frac{3}{8}-\frac{2}{5}\] \[=\boxed{\textbf{(B)}-\frac{1}{40}}\]