Question 4 (1 point) A swimmer can swim at 6.48 m/s in still water. She swims directly across a river, from north to south. The river flows east to west with a current of 3.04 m/s. If it takes the swimmer 39.9 s to cross the river, how wide is the river? [Give your answer in m, to 3 significant digits, but do not enter units with your answer.]