Question 660837: Bus trip one direction driven at 45mph. The exact same route on the return trip is driven at 55mph. The trip there took 12 minutes longer than the return trip? How do you calculate the time it took to drive round-trip?
Answer by ankor@dixie-net.com(22740)   (Show Source):
You can put this solution on YOUR website! Bus trip one direction driven at 45mph.
The exact same route on the return trip is driven at 55mph.
The trip there took 12 minutes longer than the return trip?
How do you calculate the time it took to drive round-trip?
:
Let t = time at 55 mph
then convert 12 min to hrs, 12/60 = .2 hrs
(t+.2) = the time at 45 mph
:
The distance each way is the same, write a distance equation, dist = speed * time
:
55t = 45(t+.2)
55t = 45t + 9
55t - 45t = 9
10t = 9
t = 9/10
t = .9 hrs at 55 mph (.9*60 = 54 min)
then
.9 + .2 = 1.1 hrs at 45 mph (1.1*60 = 66 min)
total time:
.9 + 1.1 = 2 hrs to drive the round trip
;
;
Confirm this by finding the actual distances, they should be equal
55 * .9 = 49.5 mi
45 * 1.1= 49.5 mi
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