Question

a steamer goes downstream and cover the distance between two ports in 4 hour while in cover the same distance upstream in 5 hour if the speed of the stream 2 kilometre per hour find the speed of the steamer in still water ​

Answer 1

Let the distance between the two ports be x km. 

Then, speed downstream = x/4 

And speed upstream = x/5 

Speed of the stream, 

= [speed downstream - speed upstream] / 2

= (x/4 - x/5)/2

Or, (5x -4x)/40 = 2

Or, x/40 = 2 

Thus, x = 80 km.

Distance between two ports = 80 km.

Answer 2

Answer :

• The distance between the two parts = 80 km.

Step-by-step explanation :

Let the speed of the stream in still water be x km/hr.

Given : Speed of the stream = 2 km/hr

∴ Speed in the downstream = (x + 2) km/hr

and speed in the upstream = (x - 2) km/hr

Distance covered downstream in 4 hours = 4 (x + 2) km

Distance covered upstream is 5 hours = 5 (x - 2) km

According to the problem, these two distance are equal.

∴ 4( x + 2) = 5( x - 2)

⟹ 4x + 8 = 5x - 10

⟹ 4x - 5x = - 10 - 8

⟹ - x = - 18

⟹ x = 18

∴ Speed of the stream = 18 km/hr.

Hence, the distance between the two parts = 4 (18 + 2) = 4 × 20 = 80 km.