A boat travels 28 km upstream in 7 hours. It travels 48 km downstream in 4 hours. Find the speed of the boat and the speed of the stream.

Answer 1

speed of boat in still water ---- x km/h
speed of current ------- y km/h

7(x-y) = 28 or
x - y = 4

4(x+y) = 48 or
x + y = 12

add them:
2x = 16
x = 8
in x+y=12, if x = 8 , y = 4

state the conclusion