To answer this item, we let x and y be the rate of the boat in still water and current, respectively. The distance traveled by the object is equal to the product of the speed and the time.
Upstream:
D = (x + y)(6)
24 = 6x + 6y
4 = x + y
Downstream:
D = (x - y)(6)
18 = 6x - 6y
3 = x - y
The values of x and y are 3.5km/h and 0.5 km/h, respectively.
Answers:
Rate in Still water = 3.5 km/h
Rate of the current = 0.5 km/h