Complex Fraction Word Problem?

SCSmith

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Joined
Oct 25, 2005
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29
Average rate= Total distance
---------------
Total time

Suppose a person travels 10 miles in 1/3 of an hour, then returns by traveling that same 10 miles in 1/4 of an hour. What is that person's average rate?

1/3 + 1/4 = 7/12 of 60mins. = 35mins total time, so 20/35 = .57

This isn't the right answer.
 
Perhaps you shouldn't have converted to minutes. Leave it in hours.

Perhaps you should include your units so that you will not confuse yourself.
 
Hello, SCSmith!


\(\displaystyle \text{Average rate}\;=\;\frac{\text{Total distance}}{\text{Total time}}\)

Suppose a person travels 10 miles in 1/3 of an hour,
then returns by traveling that same 10 miles in 1/4 of an hour.
What is that person's average rate?
You should take tkhunny's advice.

Total time: \(\displaystyle \,\frac{1}{3}\,+\,\frac{1}{4}\:=\:\frac{7}{12}\) of an hour.

Total distance: \(\displaystyle \,10\,+\,10\:=\:20\) miles.


Therefore: \(\displaystyle \,\text{Average rate} \:=\:\frac{10}{\left(\frac{7}{12}\right)} \:=\:\frac{240}{7}\:=\:34\frac{2}{7}\) miles per hour.

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What's wrong with your answer? . . . Think about it.

You had: \(\displaystyle \,\frac{20\text{ miles}}{35\text{ minutes}} \;=\;0.5714\) miles per minute.

Your answer is correct, but not the one they expected.
 
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