The upstream speed of the boat is 40 km/hr and the speed of the boat in still water is 55 km/hr. What is the downstream speed of the boat?A75 km/hrB70 km/hrC60 km/hrD65 km/hrAnswer: B. 70 km/hr Read Explanation: Let, speed of the stream = x km/hr According to the question, ⇒ 55 - x = 40 ⇒ x = 15 ∴ Downstream speed of the boat = (55 + 15) = 70 km/hrRead more in App