SOLUTION: A boy swims downstream 0.9 miles in the same amount of time that he can swim 0.6 miles upstream. If the rate of the current is 1.5 mph, how fast can he swim in still water?
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Question 456708: A boy swims downstream 0.9 miles in the same amount of time that he can swim 0.6 miles upstream. If the rate of the current is 1.5 mph, how fast can he swim in still water?
help!!! :( Answer by ankor@dixie-net.com(22740) (Show Source):
You can put this solution on YOUR website! A boy swims downstream 0.9 miles in the same amount of time that he can swim 0.6 miles upstream.
If the rate of the current is 1.5 mph, how fast can he swim in still water?
:
Let s = swim speed in still water
then
(s+1.5) = effective speed downstream
and
(s-1.5) = effective speed upstream
:
Write a time equation: time = dist/speed
: =
Cross multiply and solve for s
.9(s-1.5) = .6(s+1.5)
.9s - 1.35 = .6s + .9
.9s - .6s = .9 + 1.35
.3s = 2.25
s =
s = 7.5 mph in still water
:
Check solution by finding the times, they should be equal
.9/9 = .1
.6/6 = .1
