Question 389070: A boat travels 30 miles against a current in 5 hours. The return trip with the current takes 3 hours. If the boat travels at the same rate on both parts of the trip, what is the rate of the water current, in miles per hour?
Answer by CharlesG2(834)   (Show Source):
You can put this solution on YOUR website! A boat travels 30 miles against a current in 5 hours. The return trip with the current takes 3 hours. If the boat travels at the same rate on both parts of the trip, what is the rate of the water current, in miles per hour?
distance = rate * time
30 miles = RA * 5 hours
30/5 = 6 mph = RA, rate against current
30 miles = RW * 3 hours
30/3 = 10 mph = RW, rate with current
BR = boat rate, CR = current rate
RA = BR - CR, RW = BR + CR
6 = BR - CR, 10 = BR + CR
replace 10 - CR for BR in 1st
6 = 10 - CR - CR = 10 - 2CR
-4 = -2CR
4 = 2CR
2 mph = CR = rate of the water current
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