A man rows to a place 48 km distant and comes back in 14 hours. He finds that he can row 4 km with the stream in the same time as 3 km against the stream. The speed of the stream is:

1 km/h

According to the question,

Let the speed of the boat in still water be x km/h

Let the speed of the stream be y km/h

Speed of boat in up stream = (x - y) km/h

Speed of boat in down stream = (x + y) km/h

According to question;

Time = distance/Speed

= 4/(x−y) = 3/(x+y)

= 4x - 4y = 3x - 3y

= x = 7y -------(a)

Now;

48/(x+y) + 48/(x−y) = 14

= 48/(7y+y)  + 48/(7y−y) = 14 -------- (from eq. (a))

= 6y + 8y = 14

= 14y = 14

The speed of the stream = y = 1 km/h