Math, asked by siwach101, 2 months ago

mohit can row 25 km upstream and 35 km downstream in 2 hours . he can row 35 km downstream and 75 km upstream in 4 hrs the speed of person in still water is

Answers

Answered by bhagyashreechowdhury
1

Given:

Mohit can row 25 km upstream and 35 km downstream in 2 hours. he can row 35 km downstream and 75 km upstream in 4 hrs find the speed of a person in still water is?

To find:

The speed of a person in still water

Solution:

Let,

"x" km/hr → Speed of the person in still water

"y" km/hr → Speed of the stream

So,

Speed upstream = (x -y) km/hr

Speed downstream = (x + y) km/hr

We know,

\boxed{\bold{Time = \frac{Distance }{Speed} }}

Mohit can row 25 km upstream and 35 km downstream in 2 hours, so the equation will be:

\frac{25}{x-y} + \frac{35}{x+y} = 2

taking \frac{1}{x-y} = u \:and \: \frac{1}{x+y} = v

\implies 25u + 35v = 2 . . .  (1)

Mohit can row 35 km downstream and 75 km upstream in 4 hrs, so the equation will be:

\frac{75}{x-y} + \frac{35}{x+y} = 4

taking \frac{1}{x-y} = u \:and \: \frac{1}{x+y} = v

\implies 75u + 35v = 4 . . .  (2)

On subtracting equations (1) and (2), we get

75u + 35v = 4

25u +35v = 2

-       -          -

--------------------

50u = 2

--------------------

∴ u = \frac{2}{50} = \frac{1}{25}

On substituting the value of u in equation (1), we get

25\times \frac{1}{25}  + 35v = 2

\implies 35v = 2 -1

\implies v = \frac{1}{35}

Therefore,

\frac{1}{x - y } = u = \frac{1}{25}

\implies x - y = 25 . . . (3)

and

\frac{1}{x + y } = v = \frac{1}{35}

\implies x + y = 35 . . . (4)

On adding equations (3) and (4), we get

x - y = 25

x + y = 35

---------------

2x = 60

----------------

x = 30 km/hr

Thus, the speed of the person in the still water is → 30 km/hr.

-------------------------------------------------------------------------------------------------

Also View:

A person can row 50 kms upstream and 70 kms downstream in 4 hours. He can row 35 kms downstream and 75kms upstream in 4 hours. Find the speed of the person in still water and the speed of the current.

brainly.in/question/4874410

A boatman rows his boat 35 km upstream and 55 km downstream in 12 hours. he can row 30 km. upstream and 44 km downstream in 10 hours. find the speed of the stream and that of the boat in still water. hence find the total time taken by the boatman to row 50 cm upstream and 77 km downstream

brainly.in/question/5373531

Similar questions