Question

Speed of a boat is 5 km/hin still water and the speed of the stream is 3 km/h. if the boat takes 3 h to go to a place and come back, the distance of the place is

Answer 1

Speed upstream = speed of the boat less speed of the stream.

Speed downstream = Speed of boat plus speed of the stream.

Speed downstream = 5 + 3 = 8km/h

Speed upstream = 5 - 3 = 2km/h

Let the distance covered be x.

The time taken upstream is :

x/2 hrs

Time downstream is :

x/8 hrs

The total time taken is :

1/8x + 1/2x = 5/8 x

5/8x = 3 hrs

5x = 8 × 3

5x = 24

x = 4.8 km