3. A person is on a motoboat that is capable of a maximum speed of 10 km/h in still water, and wishes to cross a 2 km wide river to a point directly across from the starting point. If the speed of the water in the river is 6 km/h, how much time is required for the crossing, assuming the boat is moving at its maximum speed? (A) 0.25 hr (B) 0.10 hr (C) 0.35 hr (D) 0.40 hr (E) 0.50 hr