SOLUTION: A boat can travel 12 miles upstream in the same amount of time it takes to travel 18 miles downstream. If the current in the river is 3 miles per hour, find the speed of the boat i
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Question 816215: A boat can travel 12 miles upstream in the same amount of time it takes to travel 18 miles downstream. If the current in the river is 3 miles per hour, find the speed of the boat in still water. Found 2 solutions by mananth, stanbon:Answer by mananth(16946) (Show Source):
Distance against current 12
Distance with current 18
Time = same equate the time against with time with current
t=d/r
12 /(x- 3 )= 18 /(x+ 3 )
12 *(x+ 3 )= 18 *(x- 3 )
12 x + 36 = 18 x -54
12 x -18 x = -54 + -36
-6 x = -90
/ -6
x= 15 mph
m.ananth@hotmail.ca
You can put this solution on YOUR website! A boat can travel 12 miles upstream in the same amount of time it takes to travel 18 miles downstream. If the current in the river is 3 miles per hour, find the speed of the boat in still water.
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Upstream DATA:
distance = 12 miles ; rate = b-3 mph ; time = 12/(b-3) hrs.
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Downstream DATA:
distance = 18 miles ; rate = b+3 mph ; time = 18/(b+3) hrs.
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Equation::
time up = time down
12/(b-3) = 18/(b+3)
12b+36 = 18b-54
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6b = 90
b = 15 mph (speed of the boat in still water)
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Cheers
Stan H.
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