A motorboat goes downstream in river and covers a distance between to coastal towns in 5 hours . It covers this distance upstream in 6 hours . If the speed of the stream is 3 km / hr . Find the speed of the boat in still water .

The speed of the boat in still water is 33 km/h

Step-by-step explanation:

Let us denote the speed of the boat in still water as x km/h.

Thus;

Since the speed of the stream is 3 km/h, then while going downstream, the total speed on the boat would be; (x + 3) km/h

Formula for distance = speed x time

Since we are told that the time taken to cover the distance downstream is 5 hours, then;

Distance covered in 5 hours = 5(x + 3) km

Therefore, distance between A and B is 5(x + 3) km

However, while going upstream the boat will work against the water current.

Therefore, its speed upstream will be (x − 3) km/h.

we are told that the time taken to cover the distance downstream is 6 hours, then;

Distance covered in 6 hours = 6(x − 3) km

Therefore, distance between A and B is 6(x - 3) km

The true distance between A and B has to be the same.

So,

5(x + 3) = 6(x - 3)

This gives;

5x + 15 = 6x - 18

15 + 18 = 6x - 5x

x = 33

Therefore, the speed of the boat in still water is 33 km/h

x coordinate is none

step-by-step explanation: