<PRE><B>Question 66552</B>
It tok Sally 3 hours to go 75 miles down stream and it took her 5 hours to travel back upstream to her starting position.  What was the speed of her boat in still water and what was the speed of the current in the river?
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Let b be boat speed; Let c be current speed
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Down Stream DATA:
distance=75 miles ; time= 3 hrs ; rate= 75/3=35 mph
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Up Stream DATA:
distance=75 miles ; time= 5 hrs ; rate = 75/5=15 mph
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EQUATIONS:
b+c=35 mph
b-c=15 mph
Add to get:
2b=50
b=25 mph (boat speed)
b+c=25+c=35
c=10 mph (current speed)
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Cheers,
Stan H.

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