SOLUTION: The speed of a stream is 4 mph. A boat travels 3 miles upstream (against the current) in the same amount of time it takes to travel 11 miles downstream (with the current). Find the

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Question 930542: The speed of a stream is 4 mph. A boat travels 3 miles upstream (against the current) in the same amount of time it takes to travel 11 miles downstream (with the current). Find the speed of the boat in still water (no current).
ANSWER: The speed of the boat in still water is ______ mph.
Answer by mananth(16946) (Show Source):
You can put this solution on YOUR website!
boat speed x mph with no current
current speed 4 mph

against current x - 4 mph
with current x + 4 mph

Distance against current 3
Distance with current 11
Time = same equate the time against with time with current
t=d/r
3 /(x- 4 )= 11 /(x+ 4 )
3 *(x+ 4 )= 11 *(x- 4 )
3 x + 12 = 11 x -44
3 x -11 x = -44 + -12
-8 x = -56
/ -8
x= 7 mph
m.ananth@hotmail.ca