The speed of a boat is three times the flow of the stream. The time taken to travel a certain distance against the flow is three hours more than that taken while traveling with the flow. The distance covered by the boat is 48 km in each of the upstream and downstream. Find the speed of the boat and the river (in km/hr) respectively.
1
4, 12
2
12, 4
3
6, 18
4
18, 6
5
3, 9