Question

A BOATMAN ROWS TO A PLACE 48KM DISTANT AND BACK IN 14 HOURS; HE FINDS HE CAN ROW 4KM WITH THE STREAM IN THE SAME TIME AS 3KM AGAINST THE STREAM. FIND THE RATE OF THE STREAM?

please help me :(

Answer 1

If ‘v’ is the speed of the bout and ‘u’ is the speed of the stream then

48/(v+u) + 48/(v-u) = 14
4/(v+u) = 3/(v-u)

48 v =7(v+u) (v-u)
4v-4u = 3v+3u => v=7u

48•7u = 7(7u+u)(7u-u)
u=1 km/h