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A motorboat takes

3

hours to travel

108mi

going upstream. The return trip takes

2

hours going downstream. What is the rate of the boat in still water and what is the rate of the current?

Verified Answer :

irspow

108=3(b-s)

36=b-s

s=b-36

...

108=2(b+s), and using s found above gives us:

54=b+b-36

54=2b-36

2b=90

b=45, and since s=b-36, s=9

So the boat's speed is 45mph and the stream's speed is 9mph