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.
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.
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 :)