Answer:
4 miles per hour.
Explanation:
2 hours = 28 miles downstream; 14 miles per hour
3 hours = 18 miles upstream; 6 miles per hour
The boat went faster when going downstream meaning the current is going towards up stream. I would find the average speed, (14+6=20/2=10 m/h average) and determine subtract the average from the speed from wither upstream or downstream. 14- 10= 4 and 10- 6= 4. Therefore the stream's current is 4 miles per hour.