Manuel has a boat that can move at a speed of 30 kn/h in still water. He rides 280 km downstream in a river in the same time it takes to ride 70 km upstream. What is the speed of the river?

2 answers

8u=3u+35

You are solving equations with Variables on Both Sides.
Let R = speed of river

Distance = rate * time

Therefore time = Distance/rate

280/(30+R) = 70/(30-R)

Solve for R.