SOLUTION: A man travels for 8 hours at a rate of 100 miles per hour. If his average speed for the whole trip is 80 miles per hour, then how long does his return trip take?

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Question 1194984: A man travels for 8 hours at a rate of 100 miles per hour. If his average speed for the whole trip is 80
miles per hour, then how long does his return trip take?
Found 3 solutions by josgarithmetic, MathTherapy, ikleyn:
Answer by josgarithmetic(39617)   (Show Source): You can put this solution on YOUR website!
;
Answer by MathTherapy(10552)   (Show Source): You can put this solution on YOUR website!

A man travels for 8 hours at a rate of 100 miles per hour. If his average speed for the whole trip is 80
miles per hour, then how long does his return trip take?

             ----- Substituting 80 for Average Speed, 2(800) for Total Distance, and (8 + T) for Total TIme, with T being return-trip time.

Solve that for T!
Answer by ikleyn(52781)   (Show Source): You can put this solution on YOUR website!
.
A man travels for 8 hours at a rate of 100 miles per hour.
If his average speed for the whole trip is 80
miles per hour, then how long does his return trip take?
~~~~~~~~~~~~~~~ 

One way trip was 8 hours * 100 miles per hour = 800 miles long.


Hence, whole two-ways trip was 2*800 = 1600 miles.


Since the average rate for the whole trip was 80 miles per hour (as it is given in the problem),
the total travel time in both directions was 1600/80 = 20 hours.


Of these 20 hours, 8 hours was just elapced on the the trip to "there".

Hence, the trip back was 20-8 = 12 hours long.    ANSWER

Solved.

It is a simple way to solve the problem without using equations.

So, this problem/solution is accessible for 4-th grade students that didn't learn equations yet.


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                Solved in a way as it  SHOULD  be done.

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