Difference between revisions of "2007 AMC 12B Problems/Problem 2"

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2. A college student drove his compact car 120 miles home for the weekend and averaged 30 miles per gallon. On the return trip the student drove his parents' SUV and averaged only 20 miles per gallon. What was the average gas mileage, in miles per gallon, for the round trip?  
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==Problem==
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A college student drove his compact car 120 miles home for the weekend and averaged 30 miles per gallon. On the return trip the student drove his parents' SUV and averaged only 20 miles per gallon. What was the average gas mileage, in miles per gallon, for the round trip?
  
A. 22 B. 24 C. 25 D. 26 E. 28
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<math>\mathrm {(A)} 22</math>  <math>\mathrm {(B)} 24</math>  <math>\mathrm {(C)} 25</math>  <math>\mathrm {(D)} 26</math>  <math>\mathrm {(E)} 28</math>
  
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==Solution==
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The trip was 240 miles,  and <math>\dfrac{120}{30}+\dfrac{120}{20}=4+6=10</math> gallons. Therefore, the average milage was <math>\dfrac{240}{10}=24 \Rightarrow \mathrm {(B)}</math> miles per gallon.
  
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==See Also==
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{{AMC12 box|year=2007|ab=B|num-b=1|num-a=3}}

Revision as of 10:02, 17 October 2007

Problem

A college student drove his compact car 120 miles home for the weekend and averaged 30 miles per gallon. On the return trip the student drove his parents' SUV and averaged only 20 miles per gallon. What was the average gas mileage, in miles per gallon, for the round trip?

$\mathrm {(A)} 22$ $\mathrm {(B)} 24$ $\mathrm {(C)} 25$ $\mathrm {(D)} 26$ $\mathrm {(E)} 28$

Solution

The trip was 240 miles, and $\dfrac{120}{30}+\dfrac{120}{20}=4+6=10$ gallons. Therefore, the average milage was $\dfrac{240}{10}=24 \Rightarrow \mathrm {(B)}$ miles per gallon.

See Also

2007 AMC 12B (ProblemsAnswer KeyResources)
Preceded by
Problem 1
Followed by
Problem 3
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 12 Problems and Solutions