SOLUTION: A stunt driver was needed at the production site of a Hollywood movie. The average speed of the stunt driver's flight to the site was 180 mph, and the average speed of the return t

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Question 1096006: A stunt driver was needed at the production site of a Hollywood movie. The average speed of the stunt driver's flight to the site was 180 mph, and the average speed of the return trip was 120 mph. Find the distance of the round trip if the total flying time was 5 h.
Found 2 solutions by ikleyn, greenestamps:
Answer by ikleyn(52815) About Me  (Show Source):
You can put this solution on YOUR website!
.
Let D be one way distance, in miles.


D%2F180  is the time for the flight "to there",

and  D%2F120  is the time for the flight back.


In  all

D%2F180 + D%2F120 = 5 hours.


Multiply both sides by 360 to get

2D + 3D = 5*360  ====> 52D = 5*360  ====>  D = 360 miles.

Solved.

One way distance is 360 miles.

The round trip is 720 miles.

Solved.



Answer by greenestamps(13203) About Me  (Show Source):
You can put this solution on YOUR website!

Another perfectly valid solution from tutor ikleyn.... But here is a different method which, if you understand it, makes the work easier.

The key idea for this method is that, if the ratio of the speeds is a:b, and the distances are the same, then the ratio of times is b:a.

In this problem, the ratio of the speeds is 180:120, or 3:2; that means the ratio of times is 2:3.

A total of 5 hours, in the ratio 2:3, then the times are 2 hours and 3 hours.

Then you can get the distance either from 180*2 = 360 or from 120*3 = 360.