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A boat travels upstream for 30 minutes to reach a beach. The same trip traveling downstream takes 20 minutes. If the current is 4 miles per hour and the speed of the boat is constant, find the speed of the boat without any current.

 Feb 3, 2020
 #1
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Let the speed of the boat in stillwater =S
30[S - 4] =20[S + 4], solve for S
S = 20 mph - its speed in stillwater.

 Feb 3, 2020
 #2
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+1

30 minutes when travelling at S-4  miles per hour

20 mniutes when travelling S+4 miles per hour

 

Speed = distance /time

speed * time = distance

so

distance = 20(S+4)=30(S-4)

 

Now I am up to where guest started :)

 Feb 3, 2020

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