Question

Speed of a boat in still water is 10 kmph, and speed of the stream is 5 Kmph. In how many minutes
would the boat cover a distance of 5 km downstream?​

Answer 1

Answer:

The speed of the boat in still water = u = 10kmph

Let the speed of the stream itself be v

Now, we know that when an object travels downstream, the flow of the water adds to its speed and AIDS it's advance. The opposite happens when the object us travelling upstream.

So, the speed of the boat when travelling upstream and downstream becomes (u - v) and (u + v) kmph respectively.

Distance travelled upstream in time t = 16km

Distance travelled downstream in time t = 24km

We know that, for uniform motion

s = ut

For upstream:

16 = (u - v)t

For downstream:

24 = (u + v)t

Dividing these two equations:

16/24 = (u - v)t/(u + v)t

2/3 = (u - v)/(u + v)

2(u + v ) = 3(u - v)

2u + 2v = 3u - 3v

5v = u

Now, u = 10kmph

5v = 10

So, v = 2kmph

Step-by-step explanation:

Hope it's helpful to you ☺️