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Kinematics boat question

  1. Sep 24, 2013 #1
    a boat takes 3.1 hours to travel 15 km down a river, then takes 5.1 hours to travel the same distance upstream. how fast is the river traveling.

    I found the boat is traveling at 4.84km/hr down the stream and 2.94 km/hr up it. not sure where to go next.

    Any help would be appreciated.
  2. jcsd
  3. Sep 24, 2013 #2


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  4. Sep 24, 2013 #3
    Let's say the river's speed is 1 kph and the boat's speed is 2 kph then the boat will travel downstream at 3 kph and upstream at 1 kph. So when you go downstream you add the speeds, but when going upstream, you subtract the river's speed from the boat's speed. Try working that backwards.
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