premise: The river is 48 km (30 miles) long, and the 11.2-hour raft ride covers 5 km (3 miles) of navigable river that meanders through the lush countryside, where you can take in the verdant river banks and the peace and quiet.
hypothesis: The 11.2-hour raft ride will take you through 3 of the 30 mile river, where you can relax and see the beautiful countryside and green river banks.