Question

a person rowing at the rate of 5km per hr in still water takes thrice as much time in going 40 km upstream as in going 40 km downstream. find the speed of the stream.

Answer 1

Answer:

Step-by-step explanation:

let the speed of the stream is x km/hr

speed of the boat is 5km/hr (rowing speed)

now, going upstream (opposite to the stream) the speed of rowing will be

5-x km/hr

time taken to cover 40km upstream = 40/(5-x) hr

going downstream (with the stream) the speed of rowing will be 5+x km/hr

time taken to cover 40km downstream= 40/(5+x) hr

according to the given conditions

3×(40/(x+5)) = 40/(5-x)

3(5-x) = x+5

15-3x = x+5

4x = 10

x=2.5km/hr speed of the stream