SOLUTION: One boat travelling 15 mph goes 47 miles downstream in the same amount of time that another boat going 20 mph goes 40 miles upstream. How fast is the current in mph? (Round your an
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Question 729047: One boat travelling 15 mph goes 47 miles downstream in the same amount of time that another boat going 20 mph goes 40 miles upstream. How fast is the current in mph? (Round your answer to the nearest tenth of miles per hour and enter only the numerical part.) Answer by checkley79(3341) (Show Source):
You can put this solution on YOUR website! D=RT
47=(15+C)T
40=(20-C)T
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87=35T
T=87/35
T=2.5 HOURS.
47=(15+C)2.5
47=37.5+2.5C
2.5C=47-37.5
2.5C=9.5
C=9.5/2.5
C=3.8 MPH. IS THE CURRENT SPEED.
PROOF:
40=(20-3.8)2.5
40=16.2*2.5
40=40
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