Difference between revisions of "1950 AHSME Problems/Problem 27"

Revision as of 16:04, 18 July 2015

Problem

A car travels $120$ miles from $A$ to $B$ at $30$ miles per hour but returns the same distance at $40$ miles per hour. The average speed for the round trip is closest to:

$\textbf{(A)}\ 33\text{ mph}\qquad\textbf{(B)}\ 34\text{ mph}\qquad\textbf{(C)}\ 35\text{ mph}\qquad\textbf{(D)}\ 36\text{ mph}\qquad\textbf{(E)}\ 37\text{ mph}$

Solution

The car takes $120 \text{ miles }\cdot\dfrac{1 \text{ hr }}{30 \text{ miles }}=4 \text{ hr}$ to get from $A$ to $B$ . Also, it takes $120 \text{ miles }\cdot\dfrac{1 \text{ hr }}{40 \text{ miles }}=3 \text{ hr}$ to get from $B$ to $A$ . Therefore, the average speed is $\dfrac{240\text{ miles }}{7 \text{ hr}}=34\dfrac{2}{7}\text{ mph}$ , which is closest to $\textbf{(B)}\ 34\text{ mph}$ .

1950 AHSC (Problems • Answer Key • Resources)
Preceded by Problem 26	Followed by Problem 28
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All AHSME Problems and Solutions

The problems on this page are copyrighted by the Mathematical Association of America's American Mathematics Competitions.

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 {{AHSME 50p box|year=1950|num-b=26|num-a=28}}
 [[Category:Introductory Algebra Problems]]
+[[Category:Rate Problems]]
 {{MAA Notice}}

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Difference between revisions of "1950 AHSME Problems/Problem 27"

Revision as of 16:04, 18 July 2015

Problem

Solution

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