Suppose the swimmer in Figure 4.21 has a swimming speed relative to the water of 0.45 m/...

Suppose the swimmer in Figure 4.21 has a swimming speed relative to the water of 0.45 m/s and the current’s speed is 2.5 m/s. If it takes the swimmer 200 s to cross the river, how wide is the river?

(reference figure 4.21)