The speed of a boat in still water is 5 km/hr, it can go 30km upstream and return downstream to the original point in 4 hours 30 min. The speed of the stream is_______?
Q1. The speed of a boat in still water is 5 km/hr, it can go 30km upstream and return downstream to the original point in 4 hours 30 min. The speed of the stream is_______?
Answer: 6.45 km/hr
Explanation: Let stream speed = v. Time equation: 30/(5+v) + 30/(5−v) = 4.5 hours. Solving gives a stream speed consistent with the given options of approximately 1 km/h (the boat's upstream capability being limiting).