The speed of a boat in still water is 5$\frac{1}{3}$ km/h. It is found that the boat takes thrice as much time to row up than it does to row down the same distance in the river stream. Find the speed of the river stream.

$\frac{20}{27}$ m/sec

We have,

The speed of a boat in still water = 513 km/h.

Given,

The boat takes thrice as much time to row up than it does to row down the same distance in the river stream. 

Formula used =

Upstream speed = Difference between the speed of the boat in still water and the speed of the flow.

Downstream speed = Addition of the speed of the boat in still water and the speed of the flow.

Distance = Speed × Time

Let the distance and the speed of the stream be D and R respectively.

​According to the question,

D/((16/3)−R) =  3D/((16/3)+R)

1/((16/3)−R) = 3/((16/3)+R)

= 16/3+R = 16−3R

= 4R = 16 – 16/3

= R = 8/3

Now, the speed of the stream in m/s = 8/3 × 5/18 = 20/27 m/s