Find the correct relationship between given quantities. Quantity 1: Find rate of flow of the river? If a motor boat can travel at 10 km/hr in still water. It travelled 91 km downstream in a river and then returned, taking altogether 20 hrs. Quantity 2: Find speed of boat in still water? If a boat covers a certain distance downstream in 1 hr. while it comes back in 1.5 h. The speed of stream is 3km/hr.

Quantity I: Boat speed in still water is 10 km/h. Downstream speed = 10+x, upstream = 10-x. Time downstream + upstream = 91/(10+x) + 91/(10-x) = 20. Solving gives x=3 km/h. So river flow rate = 3 km/h. Quantity II: Let downstream speed = v+3, upstream = v-3. Distance downstream in 1 hr = v+3, same distance upstream in 1.5 hr gives 1.5(v-3) = v+3, so v=9 km/h. So boat speed = 9 km/h. Therefore 3 < 9, so Quantity I < Quantity II.