Example: Boat on a river
Problem: A boat is to cross a river such that it gets to a point due East of where it starts. The boat goes 5 m/s and the river flows South at 2 m/s. We’ll assume here that the river flows at a uniform speed - not faster in the middle and slower at the edges. Also, if the river is 100 meters wide, how long will it take to cross the river?