Question

a streamer goes down stream in a river, covers the distance between two towns in 20 hours. coming back upstream, it covers this distance in 25 hours. the speed of water is 4km/hour. find the distance between the two towns

Answer 1

let the speed of the streamer be x
While travelling downstream,
(4+x)=d/20
x=d/20-4

While travelling upstream,
(4-x)=d/25
x=4-d/25

d/20-4=4-d/25
d/20+d/25=4+4
(5d+4d)/100=8
9d=800
d=88.8km