motorboat takes 4 hours traveling 192 km upstream. 3 hours down stream. What is the rate of the boat in still water & what is he rate of the current

Question

A motorboat takes 4 hours to travel 192 km going upstream. The return trip takes 3 hours going downstream. What is the rate of the boat in still water and what is the rate of the current?

Answer 1

Since the rate of the water current is the same whether the boat is going up on downstream, the speed of the boat in still is the average of the upstream speed and downstream speed. 

 

upstream = 192 km/4 hours = 48 km/hour

downstream = 192 km/3 hours = 64 km/hour

 

The average of the two speeds is:

 

(48 + 64)/2 km/hr =

 

56 km/hr - This is the speed of the boat in still water

 

The current would be 8 km/hr since both the upstream and downstream speeds of the boat are 8 more or less than the speed of the boat in still water.