A man takes 4 hours and 30 minutes to row a boat a distance of 18 km downstream, and 3 hours 30 minutes to row the boat a distance of 7 km upstream. Find the speed of the stream.

1 km/h

Upstream Speed = Speed of Boat – Speed of current

Downstream Speed = Speed of Boat + Speed of current

Let the speed of the boat = x and the speed of the stream = y

According to the question,

The distance traveled downstream is 18 km. We know that the time taken to cover this distance downstream is 4 hours and 30 minutes, which is 4.5 hours.

x + y = \(\frac{18}{4.5}\) = 4 --- (A)

The distance traveled upstream is 7 km. We know that the time taken to cover this distance upstream is 3 hours and 30 minutes, which is 3.5 hours.

x - y = \(\frac{7}{3.5}\) = 2 --- (B)

From equations, A and B

x = 3 and y = 1

So the speed of the stream = 1