Kinematics boat question

[ijd5000]

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.

 

[phinds]

d=rt

 

[JizzaDaMan]

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.