Tiger Bait 10
Four doors are before you. One door leads to gold. Every other door leads to a tiger or an orc.
The door leading to gold has a true statement. Any door leading to a tiger has a false statement. Any odd-numbered door leading to an orc has a true statement; any even-numbered door leading to an orc has a false statement.
Which door leads to gold? What do the other doors lead to?
Door 1: An even number of doors lead to orcs.
Door 2: An even number of doors lead to orcs.
Door 3: An even number of doors lead to orcs.
Door 4: Considering only the statements on the first three doors, you have enough information to find the gold.
Check out the discussion on Reddit or scroll down for the answer.
The statements on the first three doors are all in agreement, so they are either all true or all false. Suppose they are all false. Then the gold must be behind door 4 and, since odd-numbered doors with false statements can’t lead to orcs, doors 1 and 3 lead to tigers. Since there must be an odd number of orcs, an orc is behind door 2.
Suppose instead that the statements are all true. Door 2 must lead to gold (it’s the only thing that could be behind an even-numbered door with a true statement), and doors 1 and 3 lead to orcs. Door 4 must then lead to a tiger.
So considering just the statements on the first three doors, we do not have enough information to solve the puzzle. This means the statement on door 4 is false, and it can’t lead to gold. That means we can eliminate the first situation where the doors are all false; the doors are all true, and gold is behind door 2. Doors 1 and 3 lead to orcs, and door 4 leads to a tiger.