SOLUTION: During the first part of a trip, a canoiest travels 100miles at a certain speed. The canoiest travels 45miles on the second part of the trip at a speed 5mph slower. The total time
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Question 471820: During the first part of a trip, a canoiest travels 100miles at a certain speed. The canoiest travels 45miles on the second part of the trip at a speed 5mph slower. The total time for the trip is 3hrs. What was the speed on each part of the trip? Answer by stanbon(75887) (Show Source):
You can put this solution on YOUR website! During the first part of a trip, a canoiest travels 100 miles at a certain speed.
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The canoiest travels 45miles on the second part of the trip at a speed 5mph slower.
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The total time for the trip is 3hrs.
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What was the speed on each part of the trip?
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1st Part DATA:
distance = 100 miles ; rate = r mph ; time = 100/r hrs
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2nd Part DATA:
distance = 45 miles : rate = r-5 mph ; time = 45/(r-5) hrs
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Equation:
time + time = 3 hrs
100/r + 45/(r-5) = 3 hrs
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100(r-5) + 45r + 3r(r-5)
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145r - 500 = 3r^2-15r
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3r^2 -160r + 500 = 0
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I graphed the quadratic and found
a realistic solution at r = 50 mph (rate on 1st part of trip)
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Then r-5 = 45 mph (rate on 2nd part of trip)
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Cheers,
Stan H.
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