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Question 115228: A boat travels 24 mi upstream in 3 hrs. then it takes 3 hrs to go downstream at 36 mi downstream, Find the speed of boat in still water and the speed of the current. (using two unknowns, write two equations and solve.)
>>>>>>>>>>>>>THANKS IN ADVANCE
Answer by stanbon(75887)   (Show Source):
You can put this solution on YOUR website! A boat travels 24 mi upstream in 3 hrs. then it takes 3 hrs to go downstream at 36 mi downstream, Find the speed of boat in still water and the speed of the current. (using two unknowns, write two equations and solve.)
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Let still water speed be "b"; Let current speed be "c"
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Upstream DATA:
Distance = 24 miles ; Time = 3 hrs ; Rate = b-c=d/t = 8 mph
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Downstream DATA:
Distance = 36 miles ; Time = 3 hrs ; Rate = b+c=d/t = 12 mph
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EQUATIONS:
b+c=12
b-c=8
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Add to get:
2b = 20
b = 10 mph (boat speed in still water)
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Substitute to solve for "c":
10+c = 12
c = 2 mph (current speed)
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Cheers,
Stan H.
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