Question

A boat takes 3 hours to travel to a certain distance with the stream, and returns to the original place in 5 hours.How long it will take to travel the same distance in stationary water?

Answer 1

LET THE SPEED OF THE BOAT IN STREAM BE Y

THE SPEED OF THE CURRENT OF THE WATER = X

THE DISTANCE TRAVELLED BY BOAT BE WITH STREAM

D= (X+Y)3

=>X+Y=D/3..............(1)

THE DISTANCE TRAVELLED BY BOAT BE AGAINST STREAM

D= (Y-X)5

=>X-Y=D/5

NOW ADDING (1)+(2)

WE GET

y=4D/15

THE SPEED OF THE BOAT IN STILL WATER =

4D/15

THE TIME REQUIRED TO COVER THE DISTANCE IN STILL WATER = D÷4D/15=15/4=3.75

IE THE REQUIRED ANSWER IS 3.75 HRS