# A man can row at 6 km/h in still water and at 4 km/h upstream. How long will the mantake to go to a place 1 km downstream and return

2
Log in to add a comment

Log in to add a comment

Certified answers contain reliable, trustworthy information vouched for by a hand-picked team of experts. Brainly has millions of high quality answers, all of them carefully moderated by our most trusted community members, but certified answers are the finest of the finest.

Speed of man in still water = 6 km/h

let the speed of river = v km/h

speed of man upstream = (6-v) km/h = 4 km/h

thus v = (6-4) km/h = 2 km/h

speed of the man downstream = (6+v) = (6+2) km/h = 8 km/h

to go 1 km downstream, time = 1/8 hour

to return 1 km upstream, time = 1/4 hour

total time = 1/8 + 1/4 = (2+1)/8 = 3/8 hours

So he will take 3/8 hours to go to a place 1 km downstream and return.

let the speed of river = v km/h

speed of man upstream = (6-v) km/h = 4 km/h

thus v = (6-4) km/h = 2 km/h

speed of the man downstream = (6+v) = (6+2) km/h = 8 km/h

to go 1 km downstream, time = 1/8 hour

to return 1 km upstream, time = 1/4 hour

total time = 1/8 + 1/4 = (2+1)/8 = 3/8 hours

So he will take 3/8 hours to go to a place 1 km downstream and return.