Problema Solution

a boats crew rowed 13.5 miles downstream with current in 1.5 hours. the return trip upstream the same distance against current took 4.5 hours. find the crews rowing rate in still water and the rate of current

Answer provided by our tutors

let


v = the crews rowing rate in still water

c = the rate of current

d = 13.5 miles the distance in one direction

t1 = 1.5 hour downstream time

t2 = 4.5 hour upstream time


downstream rate: v + c

upstream rate: v - c


since rate = distance/time


v + c = d/t1


v + c = 13.5/1.5


v + c = 9


v - c = d/t2


v - c = 13.5/4.5


v - c = 3


we have the system of equations


v + c = 9

v - c = 3


by solving it


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we find


v = 6 mph


c = 3 mph


the crews rowing rate in still water is 6 miles per hour and the rate of current is 3 miles per hour.