# Real boat situation.

**Classical Mechanics**Level 4

To cross a river of width \(b = 320 \text{ m}\), a captain steers his boat always aiming towards a point that is directly across the river from his starting point. The velocity of his boat relative to river current is \(v_{br} = 2.5 \text{ m/s}\) and river current velocity is \(v_{r} = 1.5 \text{ m/s}\) everywhere.

Determine the time \(t\) (in seconds) the boat will take to cross the river.