The Lori River is a river that is known for its unusual width of 3 km. It flows towards north at a speed of 1.8 m/s. John tried riding their OppBoat, which is a boat that is used to cross the opposite sides of the river. The boat operator drives the OppBoat due west with a velocity of 7 m/s relative to the water. How much time is required for John to cross the opposite sides of the Lori River?