A wealthy family lived in a big circular house. They had a maid, a butler, and a gardener. The parents were going to a party, so they tucked the younger kids into bed and kissed them goodnight and said goodbye, and kissed the older kids goodnight. When the parents came home, all the kids were gone—they had been kidnapped. The authorities ask the butler, maid, and gardener what they were doing at the time of the kidnapping. The butler says he was organizing the library, the maid says she was dusting the corners, and the gardener says he was watering the plants. Who’s lying and actually kidnapped the kids?

A farmer went to a market and bought a wolf, a goat, and a cabbage. On his way home, the farmer came to the bank of a river and rented a boat. But crossing the river by boat, the farmer could carry only himself and a single one of his purchases: the wolf, the goat, or the cabbage. If left unattended together, the wolf would eat the goat, or the goat would eat the cabbage. The farmer’s challenge was to carry himself and his purchases to the far bank of the river, leaving each purchase intact. How did he do it?

A farmer went to a market and bought a wolf, a goat, and a cabbage. On his way home, the farmer came to the bank of a river and rented a boat. But crossing the river by boat, the farmer could carry only himself and a single one of his purchases: the wolf, the goat, or the cabbage. If left unattended together, the wolf would eat the goat, or the goat would eat the cabbage. The farmer’s challenge was to carry himself and his purchases to the far bank of the river, leaving each purchase intact. How did he do it?