If you swim with the current in a river, your speed is increased by the speed of the water; if you swim against the current, your speed is decreased by the water's speed. The current in a river flows at 0.52 m/s. In still water you can swim at 1.73 m/s. If you swim downstream a certain distance, then back again upstream, how much longer, in percent, does it take compared to the same trip in still water?

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Netta00 Netta00 · Answer 1 · 2019-09-24T09:45:56+02:00

Answer:

11.23%

Explanation:

Lets take

Speed of man in still water =u= 1.73 m/s

Speed of flow of water = v=0.52 m/s

When swims in downward direction then speed of man = u + v

When swims in upward direction then speed of man = u - v

Lets time taken by man when he swims in downward direction is [tex]t_1[/tex] and when he swims in downward direction is [tex]t_2[/tex]

Lets distance is d and it will be remain constant in both the case

[tex]d=(u+v)t_1[/tex]

[tex]d=(u-v)t_2[/tex]

[tex](1.73+0.52)t_1=(1.73-0.52)t_2[/tex]

[tex]t_2=1.85t_1[/tex]

Time taken in still water

2 d= t x 1.73

t=1.15 x d sec

[tex]t_1=0.44d\ sec[/tex]

[tex]t_2=0.82d\ sec[/tex]

total time in current = 0.82 +0.44 d=1.26 d sec

So the percentage time

[tex]percentage\ time =\dfrac{1.28-1.15}{1.15}[/tex]

Percentage time =11.32%

So it will take 11.32% more time as compare to still current.