Question

a boat takes 6 hours to travel 24 km upstream and 36km downstream and it takes 9 hours to travel 40 km upstream and 48 km downstream find the speed of the boat in still water and the speed of the stream​

Answer 1

6 hours to travel 24 km upstream and 36km downstream

9 hours to travel 40 km upstream and 48 km downstream

let speed of boat = x

and

speed of stream = y

24/6 = 4 km/h = x-y ( upstream)

36/6 = 6 km/h = x+y (down)

so x+y/x-y = 6/4

4x+4y = 6x-6y

10y=2x

x=5y

so. x+y=6=5y+y=6y

y=1

then x= 5

same for the next section also

40/9 = x-y. and

48/9 = x+y

so

x+y=48/9. (1)

x-y= 40/9. (2)

(1)/(2) = x+y/x-y = 48/9. ÷ 40/9 = 48/40 = 12/10=5/6

so

6x+6y=5x-5y

x= -11y

it makes either X or y negative which is not possible in case of speed