A wooden raft drifts along the river. When the wooden raft passes through a wharf, a motorboat just goes down the wharf to the village 15km away from the wharf. After 0.75h, it arrives at the village and returns immediately. Then it meets the wooden raft 9km away from the village to calculate the flow rate of the river and the speed of the boat in still water

A wooden raft drifts along the river. When the wooden raft passes through a wharf, a motorboat just goes down the wharf to the village 15km away from the wharf. After 0.75h, it arrives at the village and returns immediately. Then it meets the wooden raft 9km away from the village to calculate the flow rate of the river and the speed of the boat in still water

Suppose the speed of the motorboat is V1 and the water velocity is V2, then there are: V2 + V1 = x1t1 = 150.75 = 20km / h; from the title, there are: 15 − 9v2 = 0.75 + 9v1 − V2, and the solution is: V2 = 4km / h, V1 = 16km / h. answer: the flow rate of the river is 4km / h and the speed of the boat in still water is 16km / h