Alice, Ben, and Carla each have a different pet: cat, dog, or turtle. Clues: Alice does not own the dog. Ben owns the turtle. Carla does not own the cat. Who owns the dog?
Four friends — Amy, Ben, Carl, Dana — each drink a different beverage: tea, coffee, juice, or water. Clues: Amy does not drink tea. Ben drinks coffee. Carl does not drink juice. Dana drinks water. Who drinks tea?
Three boxes are labeled: 'Apples', 'Oranges', and 'Apples and Oranges'. Every label is wrong. You may take one fruit from one box without looking inside. How can you correctly label all boxes?
On an island, every inhabitant is either a truth-teller (always tells the truth) or a liar (always lies). You meet two people: A and B. A says: 'At least one of us is a liar.' What are they?
Four cards lie on a table showing: A, D, 4, and 7. Each card has a letter on one side and a number on the other. Rule: 'If a card has a vowel on one side, it has an even number on the other.' Which cards must you turn over to test the rule?
Two guards stand before two doors. One door leads to freedom, the other to certain death. One guard always tells the truth, the other always lies, but you do not know which is which. You may ask one guard one question. What question guarantees you choose the correct door?