SOLUTION: It takes Erica 50 min to drive to work in the morning. She drives home using the same route, but it takes 21 min longer, and she averages 16 mi/h less than in the morning. How far

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Question 1173385: It takes Erica 50 min to drive to work in the morning. She drives home using the same route, but it takes 21 min longer, and she averages 16 mi/h less than in the morning. How far does Erica drive to work?
Answer by ikleyn(52810) About Me  (Show Source):
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It takes Erica 50 min to drive to work in the morning. She drives home using the same route,
but it takes 21 min longer, and she averages 16 mi/h less than in the morning. How far does Erica drive to work?
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Solution

Let "d" be the one way distance, in miles (the value under the problem's question).



Driving to work is 50 minutes;  the average rate is  d%2F50  miles per minute.

Driving back    is 71 minutes;  the average rate is  d%2F71  miles per minute.



The difference of the average rates is  d%2F50 - d%2F71  miles per minute.

According to the condition, this difference is  16 miles per hour,  or  16%2F60  miles per minute.



So, you have this equation


    d%2F50 - d%2F71 = 16%2F60.



To solve it, multiply both sides by 50*71*60. You will get


    60*71*d - 60*50*d = 16*50*71

    (60*71 - 60*50)*d = 16*50*71


           d          = %2816%2A50%2A71%29%2F%2860%2A71-60%2A50%29 = 45.079.


ANSWER.  One-way distance is  45.079 miles.

Solved.