SOLUTION: Billy took a boat to Cuba. It took him 6 hours to travel 80 km against the current and on the way back it took 2 hours. What is the average speed of the boat in still water and wha

Algebra ->  Coordinate Systems and Linear Equations  -> Linear Equations and Systems Word Problems -> SOLUTION: Billy took a boat to Cuba. It took him 6 hours to travel 80 km against the current and on the way back it took 2 hours. What is the average speed of the boat in still water and wha      Log On


   

Question 938614: Billy took a boat to Cuba. It took him 6 hours to travel 80 km against the current and on the way back it took 2 hours. What is the average speed of the boat in still water and what is the speed of the current?
Answer by stanbon(75887) About Me  (Show Source):
You can put this solution on YOUR website!
Billy took a boat to Cuba. It took him 6 hours to travel 80 km against the current and on the way back it took 2 hours. What is the average speed of the boat in still water and what is the speed of the current?
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Against current DATA:
time = 6 hrs ; dist = 80 km ; rate = 80/6 = 40/3 km/hr
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With current DATA:
time = 2 hrs ; dist = 80 km ; rate = 80/2 = 40 km/hr
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Equations:
Against:: b - c = 40/3 km/hr
With::::: b + c = 40 km/hr
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Add to solve for "b"::
2b = 160/3
b = 80/3 km/hr (speed of the boat in still water)
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Subtract to solve for "c"::
2c = (2/3)40
c = (1/3)40
c = 13 1/3 km/hr (speed of the current)
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cheers,
Stan H.
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