Question

A streamer goes downstream from point A to B in 9 hours. From B to A, upstream, it takes 10 hours. If the speed of the streamer is 1 km/h, what will be the speed in still water ? Also find the distance between the points A and B.

Answer 1

Let x be the speed of streamer in still water.
Given that speed of streamer =1 km/h
We know during downstream,the speed of stream gets added to speed in still water,
Therefore speed of streamer in downstream=(x+1) km/h
During upstream,the speed of stream gets subtracted from the speed of streamer,
therefore speed in upstream=(x-1) km/h
We know distance travelled in both upstream and downstream is same.
I.e 9(x+1)=10(x-1)
I.e. 9x+9=10x-10
I.e .x=19
I.e. Speed of streamer in still water is 19 km/h
Distance between A and B is 9(x+1)=9*20=180 km