Question

A boat goes downstrem and reaches a fixed point in a river in 40min , turn back and again sails upstream to reach the starting point. The speed of the stream is constant all the time and is 1|5 times the speed of the boat. By what percent the speed of the boat should be increased in upstream so that it take same time to reach the starting point as it took in downstream​

Answer 1

Answer:

39/5

Step-by-step explanation:

1/5-40

Answer 2

Answer:

The boat should increase its speed by 40 % in Upstream.

Explanation:

What is Upstream and Downstream and Stream Velocity(speed)?

It is referred to as being upstream when the boat is moving downstream of the stream. Here, the term "upstream speed" refers to the boat's net speed.

The term "downstream" refers to a boat that is moving in the stream's direction.

The speed of the water in a stream is known as stream velocity. The units are time and distance (e.g., metres per second or feet per second). Due to friction, stream velocity is highest in the middle of the stream, close to the surface, and slowest along the stream bottom and banks.

Speed of the boat is x m/min.

Therefore, Speed of the stream is $\frac{x}{5}$ m/min.

Time travelled in Downstream is 40 min

Distance travelled in downstream = $40 *(x +\frac{x}{5}) = 40 *\frac{6x}{5} = 48x$ m .

In upstream distance travelled is $48x$ m.

Total time taken = 40 mins

Speed in upstream is = $\frac{Total \ distance}{Total \ time}$ = $\frac{48x}{40} = \frac{12x}{10} = 1.2x$.

Speed of boat in upstream is y m/min. (say)

Therefore,

$y - \frac{x}{5} = 1.2x$

⇒ $y = 1.2x +.2x$

⇒ $y = 1.4x$.

Incresed Speed of the boat is $1.4x - x = .4x$

Percentage increse in the speed of the boat is = $\frac{.4x}{x}* 100 = .4 *100 = 40%$%.

To reach the starting point in the same amount of time the boat should increase its speed by 40 % in Upstream.

To learn more about Upstream and Downstream refer to :

https://brainly.in/question/12186743?referrer=searchResults

https://brainly.in/question/10869548?referrer=searchResults

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