SOLUTION: A steamer goes downstream from one point to another in 9 hours. It covers the same distance upstream in 10 hours. If the speed of the stream be 1 km/hr , find the speed of the stea

Let D be the distance between the ports (in kilometers), and
let u be the streamer speed in still water.

Then you have these two equations


 = u + 1,   (1)    ( speed equation for moving downstream )

 = u - 1,  (2)    ( speed equation for moving upstream )

Distract equation (2) from (1) (both sides). You will get

 = 2  --->   = 2  --->   = 2  --->  D = 2*90 = 180.

Thus we found the distance. It is 180 kilometers.

Now from (1),

 = u + 1  ---> 20 = u + 1  --->  u = 20-1 = 19.

The treamer speed in still water is 19 .