You walk into a dark room holding a single match. Inside, there is an oil lamp, a gas heater, and a wood-burning stove. Which one do you light first?

You have 12 identical-looking coins. Eleven weigh the same, but one is counterfeit and has a different weight (either lighter or heavier). Using a balance scale, what is the minimum number of weighings required to guarantee finding the fake coin and determining if it is light or heavy?

Five runners finish a school marathon, and only these facts survive. Jonas finished ahead of Nico. Elena finished ahead of Jonas. Mara finished ahead of Dmitri. Nico finished ahead of Mara. Who finished last?

A shepherd needs to cross a river with a wolf, a goat, and a cabbage. However, his boat can only hold himself and one item at a time. If left alone, the wolf eats the goat, and the goat eats the cabbage. How can the shepherd cross safely in the fewest round trips?

Three people check into a hotel room that costs $30 total. They each pay $10. Later, the manager realizes there was a promotion and the room should only cost $25. He gives the bellhop $5 in single dollar bills to return to the guests. On the way up, the dishonest bellhop keeps $2 for himself and gives $1 back to each of the three guests. Now, each guest has paid $9 (total $27), and the bellhop has $2, which equals $29. Where did the missing $1 go?

Anna, Ben, and Carl each hold a card numbered 1, 2, or 3. No two cards are the same. Anna says, 'My number is higher than Ben's.' Ben says, 'My number is not 1.' Carl says, 'My number is 1.' If only one of them is lying, what number does Ben hold?

I have a long cape, sharp teeth, and I sleep in a coffin by day. What am I?