SOLUTION: Phil is taking a 40-kilometer canoe trip. If he travels at 30 kilometers per hour for the first 10 kilometers and then at 15 kilometers per hour for the rest of the trip, how many

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Question 470916: Phil is taking a 40-kilometer canoe trip. If he travels at 30 kilometers per hour for the first 10 kilometers and then at 15 kilometers per hour for the rest of the trip, how many minutes longer will it take him than if he makes the entire trip at 20 kilometers per hour?
Answer by ptaylor(2198) About Me  (Show Source):
You can put this solution on YOUR website!
Distance (d) equals rate (r) times time (t) or d=rt; r=d/t and t=d/r
Time it takes to travel 10 kilometers at 30 kilometers per hour:
t=d/r=10/30=1/3 hour=20 min
Time it takes to travel 30 kilometers at 15 kilometers per hour:
t=d/r=30/15=2 hours
Total time for the trip=20 min + 2 hr=2 hr 20 min
Time it takes to travel 40 kilometers at 20 kilometers per hour:
t=d/r=40/20=2 hours
Total time for the trip =2 hr
Ans: 2 hr 20 min minus 2 hr=20 min
It takes him 20 min longer
Hope this helps--ptaylor