Question

a race boat covers a distance of 60 km downstream in one and a half hours. it covers the same distance upstream in two hours . the speed of the race boat in still water is 35 km/hr . find the speed of the stream

Answer 1

Hy

Let The Speed Of Stream Be x km/hr.

Now Speed Upstream = 35-x

Speed Downstream = 35+x

Now Time = Distance/Speed

3/2 = 60/35+x

And

2 = 60/35-x

Cross Multiplying We Get

105+3x = 120

3x = 15

x = 5

Check By Solving Other Equation

2 = 60/35-x

70-2x = 60

2x = 10

x = 5

So

Speed Of Stream = 5km/hr

Answer 2

Answer:

=> 5 km/hr

Step-by-step explanation:

According to the question:

It is given that,

The distance covered = $60$km

The time is taken ( for downstream ) = $1.5$ hours

And the time is taken ( for upstream ) = $2$ hours

As we have to find the speed of the streams,

Therefore,

Speed downstream = $\frac{60}{1.5}=40 km/hr$

And the upstream speed = $\frac{60}{2}=30km/hr$

We know that,

The speed of the stream,

$=> \frac{1}{2}[40-30]$

=> 5 km/hr

Hence, the speed of the stream is 5km/hr.