Question

a motorboat whose speed is 18 kilometre per hour in still water takes 1 hour more to go 24 km upstream then to return downstream to the same spot find the speed of the stream ​

Answer 1

Answer:

Hope it helps you

Sorry for the handwriting

S= speed

D= distance

T= time

Sorry it is +24x and not - 24x

At the end (lcm)

Answer 2

↦Solution : -

Let the speed of the stream be = x km/h

Then, the speed of the boat upstream = (18-x) km/h

Speed of the boat downstream = (18+x) km/h

Formula = Distance/Speed

The time taken to go upstream = 24/18-x hours

The time taken to go downstream = 24/18+x hours

According to the question : -

(24/18-x) - (24/18+x) = 1

24(18+x) - 24(18-x) = (18-x) (18+x)

x² + 48x - 324 = 0

Using Quadratic Formula : -

x = -48 ± √48²+1296/2 = -48 ± √3600/2

-48 ± 60/2

= 6 or -54

Since , x is the speed of the stream , it cnnot be negative. So , we ignore the root x = -54 ..

Therefore , the speed of the stream is 6km/h