Read the hints in the riddle and leave your answer in the comment section.
There is a boat with a ladder attached to it, the ladder is eight feet tall.
If the water rises four feet how much of the ladder will be on top of the water?
The ladder is on top the boat and as the water level rises the boat will also rise.
So the ladder will also rise with the boat, so it will still be out of water, so answer is 8 feet above water.
Solving the boat riddle will improve your logical reasoning skills, it will also help you to think out of the box.