Difference between revisions of "2014 AMC 10A Problems/Problem 5"

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==Solution==
 
==Solution==
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[[WLOG]] let there be <math>100</math> students who took the test. We have <math>10</math> students score <math>70</math> points, <math>35</math> students score <math>80</math> points, <math>30</math> students score <math>90</math> points and <math>25</math> students score <math>100</math> points. The median is easy to find by simply eliminating members from each group. The median is <math>90</math> points. The mean is just <math>\dfrac{700+2800+2700+2500}{100}=7+28+27+25=87</math>. The difference is <math>90-87=\boxed{\textbf{(C)}\ 3}</math>
  
 
==See Also==
 
==See Also==

Revision as of 23:34, 6 February 2014

Problem

On an algebra quiz, $10\%$ of the students scored $70$ points, $35\%$ scored $80$ points, $30\%$ scored $90$ points, and the rest scored $100$ points. What is the difference between the mean and median score of the students' scores on this quiz?

$\textbf{(A)}\ 1\qquad\textbf{(B)}\ 2\qquad\textbf{(C)}\ 3\qquad\textbf{(D)}}\ 4\qquad\textbf{(E)}\ 5$ (Error compiling LaTeX. Unknown error_msg)


Solution

WLOG let there be $100$ students who took the test. We have $10$ students score $70$ points, $35$ students score $80$ points, $30$ students score $90$ points and $25$ students score $100$ points. The median is easy to find by simply eliminating members from each group. The median is $90$ points. The mean is just $\dfrac{700+2800+2700+2500}{100}=7+28+27+25=87$. The difference is $90-87=\boxed{\textbf{(C)}\ 3}$

See Also

2014 AMC 10A (ProblemsAnswer KeyResources)
Preceded by
Problem 4
Followed by
Problem 6
1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25
All AMC 10 Problems and Solutions

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