Question

shayam can row downstream 50km in 5hrs and upstream 18km in 3hrs find his speed of rowing in still water and the speed of the current​

Answer 1

Answer:

let speed of shyam is x km/h

and speed of water is y

speed of shyam in downstream is (x-y) km/h

speed of shyam in upstream is ( x+y) km/h

according to question

5x-5y=50 first equation

3x+3y=18 second equation

after multipling 3 in equation first and 5 in equation second

15x-15y=150

15x+15y=90

after addition of equations

30x=240

x=8km/h

3y=18-24

y=-2 km/h

Answer 2

Question:

Shayam can row downstream 50km in 5hrs and upstream 18km in 3hrs. Find his speed of rowing in still water and the speed of the current.

Answer:

The speed of Shayam in still water and the speed of the current is 8 km/hr and – 2 km/hr respectively.

Step-by-step explanation:

Let :

➻ Speed of him in still water be a km/hr

➻ Speed of current be b km/hr

So, now :

➻ Speed upstream = (a + b) km/hr

➻ Speed downstream = (a – b) km/hr

Given, he can row upstream 18km in 3hrs, so :

➻ Speed = Distance/Time

➻ (a + b) = 18/3

➻ a + b = 6

Also, he can row upstream 50km in 5hrs, so :

➻ Speed = Distance/Time

➻ (a – b) = 50/5

➻ a – b = 10

Now, the pair of linear equations in two variables are :

➻ a + b = 6 . . . . . . ➊

➻ a – b = 10 . . . . . . ➋

Let's get the value of 'a' from ① :

➻ a + b = 6

➻ a = 6 – b

Now, substituting the value of 'a' in ② :

➻ a – b = 10

➻ (6 – b) – b = 10

➻ 6 – 2b = 10

➻ – 2b = 10 – 6

➻ – 2b = 4

➻ b = 4/– 2

➻ b = – 2

Finally, substituting the value of 'b' in ② :

➻ a – b = 10

➻ a – (– 2) = 10

➻ a + 2 = 10

➻ a = 10 – 2

➻ a = 8

★ Therefore, the speed of rowing in still water is 8 km/hr and speed of the current is – 2 km/hr.