SOLUTION: Ryan drives to Pittsburgh at 55 mph and returns by a road 10 miles shorter at 60 mph. The return trip takes 30 minutes less. How long is each road?

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Question 153960: Ryan drives to Pittsburgh at 55 mph and returns by a road 10 miles shorter at 60 mph. The return trip takes 30 minutes less. How long is each road?
Answer by ankor@dixie-net.com(22740) About Me  (Show Source):
You can put this solution on YOUR website!
Ryan drives to Pittsburgh at 55 mph and returns by a road 10 miles shorter at 60 mph. The return trip takes 30 minutes less. How long is each road?
:
let d = distance of the original trip
then
(d-10) = distance of the return trip
:
Convert 30 min to hrs; .5 hrs
:
Write a time equation:
:
to time = return time + one-half hr
d%2F55 = %28%28d-10%29%29%2F60 + .5
:
Multiply equation by 3300 to get rid of the denominator (55*60)
60d = 55(d-10) + 3300(.5)
:
60d = 55d - 550 + 1650
:
60d - 55d = 1100
d = 1100%2F5
d = 220 mile is the original trip and 210 miles is the return trip
:
:
Check solution by finding the time for each trip
220/55 = 4 hrs
210/60 = 3.5 hrs