In a river, a boat covers 8 km in 40 mins while travelling downstream, but takes 1 hr to make the return journey (upstream). If the speed of the boat and the flow of the river are uniform , find the speed of the boat in still water and the speed of the stream please.
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Answer:
We have a boat covers 8 km in 40 min, while travelling downstream, but takes 1 hr to make the return journey, if the speed of the boat and flow of river is uniform, find the speed of the boat in still water and speed of the stream.
As it is given speed of river & boat are uniform
⇒let speed of boat in still water=u km/h
⇒let speed of river =v km/h
In downstream boat floats in direction of river flow, their speeds add up, speed of boat=(u+v) km/h
In upstream boat floats in opposite direction of river flow,their speeds=boat speed −river speed
⇒speed of boat=(u−v) km/h x [in return distance would be 8 km only]
Distance covered in downstream = 8 km
⇒speed x time = 8
⇒(u + v)4060 = 8
⇒u + v = 12 ...(1)
Distance covered in upstream = 8 km
⇒(u − v) x 1 = 8
⇒u − v = 8 ...(2)
Add (1) and (2), we get
2u = 20
⇒u = 10 km/h
Now, from (1), we get
v = 2 km/h
Speed of boat = 10 km/h
speed of river = 2 km/h
Step-by-step explanation:
Answer:
Step-by-step explanation:
