Question

a streamer going downstream in a river cover the distance between two towns in 15 hours coming back upstream it covers the distance in 20 hours the speed of the water is 3 kilometre per hour . find the distance between two towns​

Answer 1

360 km

Explanation:

Let stream speed = x

Speed of water = 3km/hr

Therefore,

Upstream speed = (x - 3) km/hr

Downstream speed = (x + 3) km/hr

Time taken downstream = 15 hours

Time taken upstream = 20 hours

Recall:

Distance = speed * time

Upstream Distance = downstream distance

20(x - 3) = 15(x + 3)

20x - 60 = 15x + 45

20x - 15x = 45 + 60

5x = 105

x = 105 / 5

x = 21

Upstream speed = (21 - 3) = 18

Distance between the two towns :

18 * 20 = 360 km