Question

It takes 12 hours for a boat to travel a certain distance in the down stream and it takes 24 hours to return 24 hours to return . How long will it take for the Boat to cover the same distance in still water ? 

Answer 1

We know,Distance ÷ Time = Speed

Let speed of the boat be X kmph and speed of the stream be Y kmph.

Downstream speed =X+Y= D/12

Upstream speed= X- Y=D/24

Downstream Speed + Upstream speed = 2X =D/12+D/24

48X =2D+D

=> 3D = 48X hence D = 16X or D/X=16

Since X = Speed of the boat in still water, it will take 16 hours for the boat to cover the distance in still water.

 

X= Speed of the boat in still water, it will take 16 hours for the boat to cover the distance in still water.