Question

A motor bort whose speed is 15km per hour in still water goes 30 km down stream and come back is a total time of 4 hour 30 minutes find the speed of stream

Answer 1

Answer:

Step-by-step explanation:

Answer 2

Answer:

The speed of stream is 5 km/hr

Step-by-step explanation:

Let speed of steram be x

We know that,

                      speed of boat upstream: 15-x

                      speed of boat downstream:15-x

                      time = distance/speed

So, according to question,

=> (30/15+x) + (30/15-x) = 9/2                                {4 1/2 =9/2}

=> {30(15+x)+30(15+x)}/{(15)^2 - x^2} = 9/2

=> 900/225-x^2 = 9/2

=> 1800 = 9(225-x^2)

=> 2025-9x^2 = 1800

=> 9x^2 = 225

=> x^2 = 25

=> x = + or - 5    

But speed can't be negative.

Therefore, x = 5

So, speed of the stream is 5 km/h

Hope this helps you :)