SOLUTION: A car travels up a hill at a constant speed of 30mi/hr and returns down the hill at a speed of 60 mi/hr. the road to the top of the hill is 15 miles. Calculate the total time for

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Question 554530: A car travels up a hill at a constant speed of 30mi/hr and returns down the hill at a speed of 60 mi/hr. the road to the top of the hill is 15 miles. Calculate the total time for th whole trip.
Answer by Alan3354(69443) About Me  (Show Source):
You can put this solution on YOUR website!
A car travels up a hill at a constant speed of 30mi/hr and returns down the hill at a speed of 60 mi/hr. the road to the top of the hill is 15 miles. Calculate the total time for th whole trip.
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t = d/r
15/30 = 0.5 hr going up
15/60 = 0.25 hr coming down
--> 0.75 hours
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Notice that the average speed for the round trip is 40 mi/hr, not 45.