SOLUTION: A motorboat goes 36 km downstream in the same amount of time it takes to go 24 km upstream. If the current is flowing 3 km/h, what is the speed of the boat in still water?

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Question 375231: A motorboat goes 36 km downstream in the same amount of time it takes to go 24 km upstream. If the current is flowing 3 km/h, what is the speed of the boat in still water?
Answer by Fombitz(32388) About Me  (Show Source):
You can put this solution on YOUR website!
Rate*Time=Distance
.
.
R%2At=D
Let B be the speed of the boat.
With the current,
%28B%2B3%29%2At=36
t=36%2F%28B%2B3%29
Against the current,
%28B-3%29%2At=24
t=24%2F%28B-3%29
Equate the two times,
36%2F%28B%2B3%29=24%2F%28B-3%29
36%28B-3%29=24%28B%2B3%29
3%28B-3%29=2%28B%2B3%29
3B-9=2B%2B6
highlight%28B=15%29kph