What is the downstream speed of a boat when the speed of the boat in still water is 10 m/s and the speed of the river is 20% of the speed of the boat?A8 m/sB12 m/sC4 m/sD9 m/sAnswer: B. 12 m/s Read Explanation: The speed of the boat in still water = 10 m/s The speed of the river = 20% of 10 m/s = 2 m/s ⇒ Downstream speed = (10 + 2) = 12 m/sRead more in App