2011 AMC 10B Problem 1

Attempt Problem 1 of the 2011 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 2011 AMC 10B solutions, or check the answer key.

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1.

What is the value of the following expression? 2+4+61+3+51+3+52+4+6\dfrac{2+4+6}{1+3+5} - \dfrac{1+3+5}{2+4+6}

1-1

536\dfrac{5}{36}

712\dfrac{7}{12}

14760\dfrac{147}{60}

433\dfrac{43}{3}

Answer: C
Concepts:fractionorder of operations
Difficulty rating: 660
Small Hint:

Add the even numbers and odd numbers first

Big Hint:

The expression becomes 129912\frac{12}{9}-\frac{9}{12}

Solution:

Simply solving directly: 2+4+61+3+51+3+52+4+6=129912=1612912=712.\begin{aligned} &\dfrac{2+4+6}{1+3+5} - \dfrac{1+3+5}{2+4+6} \\ &= \dfrac{12}9 - \dfrac 9{12} \\ &= \dfrac {16}{12} - \dfrac 9{12} \\ &=\dfrac 7{12}. \end{aligned}

Thus, the correct answer is C .

Full Exam

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