A boat takes 6 hours to cover 288 km downstream and 7 hours to cover 168 km upstream. Find the time taken by the boat to cover 180 km in still water.

Solution

ATQ, First find the downstream speed and upstream speed. Downstream distance = 288 km Downstream time = 6 hours Downstream speed = 288/6 = 48 km/h Upstream distance = 168 km Upstream time = 7 hours Upstream speed = 168/7 = 24 km/h In boat and stream questions: Speed in still water = (Downstream speed + Upstream speed) / 2 So, Speed in still water = (48 + 24) / 2 Speed in still water = 72/2 Speed in still water = 36 km/h Now the boat has to cover 180 km in still water. Time = Distance / Speed Time = 180/36 Time = 5 hours