This puzzle is best visualized using an "extreme case." For example, imagine that the rock you have is small, but extremely heavy. You can also picture a boat in a small container, rather than a large lake. That should help you reach the solution. But to get the solution spelled out, watch the video below.
Can You Solve The Boat Puzzle?
Will the water rise or will the boat rise?
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Key Facts In This Video

Archimedes' Principle states that the buoyant force on an object underwater is equal to the weight of the volume of water that the object displaces. 01:06

Using an "extreme case" to approach a problem allows people to visualize the problem's elements and solve it more easily. 01:59

Here are two more problems that lend themselves well to "extreme case" solving: 03:25
The Infuriating Monty Hall Problem
Many people find the solution to this one hard to believe.
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Key Facts In This Video

The Monty Hall problem is named after the host of the gameshow "Let's Make a Deal." 00:03

The Monty Hall problem states that, given three doors with a prize behind one of them, you should always switch doors from your initial pick once you're shown a door that doesn't have the prize behind it. 01:49

Watch a helpful visualization of the Monty Hall problem that involves 100 instead of 3 doors: 03:14
The Three Switches Puzzle
There's no math involved here, just logic.
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