Logic puzzles and brain teasers

Albert knows the month, Bernard knows the day. Can you determine Cheryl’s birthday from their conversation?

100 prisoners are isolated, but one light switch may let them prove everyone has visited the room.

Can 31 dominoes cover a chessboard with two opposite corners removed?

Five pirates must divide 100 gold coins. What should the smartest pirate propose to survive and keep the most?

100 prisoners may each open 50 boxes to find their own number. Can a strategy save them all?

Everyone can see others’ eye colors, but not their own. One public statement changes everything.

Two ropes each burn for 60 minutes, but not at a uniform rate. Can you measure exactly 45 minutes?

A line of prisoners must guess their hat colors. Can they use strategy to save as many people as possible?

Three gods are named True, False, and Random. Can you identify each of them using only three yes-or-no questions?

You choose 1 of 3 doors. The host opens a goat door. Should you switch or stay?

One of 12 coins is counterfeit and may be heavier or lighter. Can you find it in just 3 weighings?

You have 1000 wine bottles, one is poisoned, and 10 test subjects. Can you find the poisoned bottle in one round?