A motor boat in still water travels at a speed of 36 km./hr. It goes 56 km. upstream in 1 hours 45 minutes. The time taken by it to cover the same distance down the stream will be-

दिया है: नाव की speed in still water = 36 km/hr, upstream distance = 56 km, upstream time = 1 hour 45 minutes = 7/4 hours। Upstream speed = 56 / (7/4) = 32 km/hr। Therefore stream speed = 36 - 32 = 4 km/hr। Downstream speed = 36 + 4 = 40 km/hr। Downstream time = 56 / 40 = 1.4 hours = 1 hour 24 minutes। अगर stream speed a है तो upstream speed = boat_speed - a और downstream = boat_speed + a।