A steamer can go 24 km in still water in 50 minutes. One day, it went 22.5 km upstream and returned the same distance downstream. If the difference between the time taken to travel upstream and downstream was 25 minutes, then what was the speed of the stream in km per hour?
1
10.5 km/h
2
7.2 km/h
3
9.8 km/h
4
3.5 km/h
5
10 km/h