SOLUTION: a barge takes 3 hours to move (at a constant rate) downstream for 27 miles, helped by a current of 3 miles per hour. if the barges engines are set at the same pace, find the time o

Algebra ->  Coordinate Systems and Linear Equations  -> Linear Equations and Systems Word Problems -> SOLUTION: a barge takes 3 hours to move (at a constant rate) downstream for 27 miles, helped by a current of 3 miles per hour. if the barges engines are set at the same pace, find the time o      Log On


   

Question 858469: a barge takes 3 hours to move (at a constant rate) downstream for 27 miles, helped by a current of 3 miles per hour. if the barges engines are set at the same pace, find the time of its return trip against the current
Answer by jim_thompson5910(35256) About Me  (Show Source):
You can put this solution on YOUR website!
With The Current:


D = r*t


27 = (r+3)*3


27/3 = r+3


9 = r + 3


9-3 = r


6 = r


r = 6


So the speed of the barge (with no current) is 6 mph.


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Against The Current:


D = r*t


27 = (r - 3)*t


27 = (6 - 3)*t


27 = 3*t


27/3 = t


9 = t


t = 9


It will take 9 hours for the barge to go against the current.