A boat can row 80 km upstream in 8 hours and the same distance downstream in 4 hours. What is the speed (in km/hr) of the boat in still water?
Show answer & explanation
Correct answer: B
Explanation
Speed against the current = 80 / 8 = 10 km/h
Speed with the current = 80 / 4 = 20 km/h
Speed of the boat in still water = (20 + 10) / 2= 15 km/h