Architecting: Brain Food

The Three Gods Logic Puzzle

Wed, 22 May 2024 03:42:34 GMT

You meet three gods. One always tells the truth, one always lies, and one answers randomly. You can ask three yes-or-no questions, each directed to any god. They answer "ja" or "da," but you don't know which means yes or no. How can you determine who is who?

Answer: This is a complex logical puzzle involving framing questions such that no matter who you …

The Three Switches

Wed, 15 May 2024 03:05:57 GMT

You are in a basement with three light switches, each corresponding to one of three light bulbs in the attic. You can't see the bulbs from the basement. How can you tell which switch corresponds to which bulb with only one trip to the attic?

Answer: Turn on one switch and wait a few minutes. Turn it off, turn on another, and go to the attic. The lit bulb…

The Famous Fox, Goose and Bag of Beans Puzzle

Wed, 08 May 2024 00:16:25 GMT

A farmer must transport a fox, a goose, and a bag of beans across a river. His boat is only big enough for him and one other item. If left unattended together, the fox will eat the goose, or the goose will eat the beans. How does he get all three across the river without losing any of them?

Answer: First, he takes the goose across, leaves it on the other…

The Famous River Crossing

Tue, 30 Apr 2024 22:05:47 GMT

A wolf, a sheep, and a cabbage need to be taken across the river by a farmer in a small boat. The boat can only carry the farmer and one other item at a time. The wolf can't be left alone with the sheep, and the sheep can't be left alone with the cabbage. How does the farmer do it?

Answer: First, take the sheep across, leave it, and return alone. Then ta…

The Broken Chessboard

Wed, 24 Apr 2024 08:56:31 GMT

A standard 8x8 chessboard has two opposite corners removed. Is it possible to cover the remaining board with 31 dominoes, each covering two squares?

Answer: No. Removing two opposite corners, which are of the same color, leaves 30 of one color and 32 of the other. Each domino covers one of each color, so it's impossible to cover the board.

The Infinite Hotel Paradox

Wed, 17 Apr 2024 07:08:44 GMT

A hotel has an infinite number of rooms and all are occupied. A new guest arrives. How does the hotel manager accommodate the new guest without asking any guest to leave?

Answer: The manager moves the guest in room 1 to room 2, room 2 to room 3, and so on, ad infinitum. This frees up room 1 for the new guest.

The Two Doors and Two Guards

Wed, 10 Apr 2024 06:50:32 GMT

You're standing in front of two doors. One door leads to certain death and the other to freedom. You don't know which is which. There are two guards, one by each door. One always tells the truth, the other always lies. You can ask one guard one question to determine which door is safe. What do you ask?

Answer: Ask either guard, "If I asked the other guar…

The Hundred Coins Puzzle

Wed, 03 Apr 2024 06:10:55 GMT

You have 100 coins lying flat on a table, each with a head side and a tail side. 10 of them are heads up, 90 are tails up. You cannot feel, see, or in any other way find out which side is up. Split the coins into two piles such that there are the same number of heads in each pile.

Answer: Split the coins into a pile of 90 and a pile of 10. Then flip all …

I am not alive, but I can grow; I don't have lungs, but I need air; I don't have a mouth, but water kills me. What am I?

Wed, 13 Mar 2024 18:31:20 GMT

Answer: Fire.

The Infinite Chocolate Bar

Wed, 06 Mar 2024 18:30:21 GMT

You have a chocolate bar that consists of a 5x2 array of squares. You can break the chocolate bar along any row or column. What is the least number of breaks needed to separate each of the squares?

Answer: 9 breaks. Each break separates one square until the last square remains.

The Seven Candles

Wed, 28 Feb 2024 18:30:27 GMT

You have a 7-minute hourglass and an 11-minute hourglass. How do you measure exactly 15 minutes?

Answer: Start both hourglasses. When the 7-minute hourglass runs out, turn it over (7 minutes elapsed). When the 11-minute hourglass runs out, turn the 7-minute one over again (11 minutes elapsed, with 4 minutes left in it). When the 7-minute hourglass runs o…

The Three Gods Riddle

Wed, 21 Feb 2024 18:30:21 GMT

Three gods A, B, and C are called, in no particular order, True, False, and Random. True always speaks truly, False always speaks falsely, but whether Random speaks truly or falsely is a random matter. Your task is to determine the identities of A, B, and C by asking three yes-no questions; each question must be put to exactly one god. The gods understa…

The Balanced Beam

Mon, 11 Dec 2023 12:53:22 GMT

The Balanced Beam: A beam balances perfectly on a fulcrum. On one end is a basket with a 10-pound rock. On the other end, a 2-pound rock. How can you make the 2-pound rock side hit the ground without touching either rock, and the beam remains balanced afterward?

Answer: Move the fulcrum to the side of the 2-pound rock. The longer arm will make its lighte…

The Airplane Fuel Puzzle

Mon, 11 Dec 2023 10:45:08 GMT

The Airplane Fuel Puzzle: An airplane can carry enough fuel for exactly half of the globe. It has a unique refueling system that allows fuel transfers in mid-air. What is the minimum number of airplanes required to get one plane around the globe, assuming all airplanes depart from the same airport and need to return?

Answer: Three airplanes. They fly tog…

The Poisoned Wine

Mon, 11 Dec 2023 06:29:24 GMT

The Poisoned Wine: A king has 1000 bottles of wine and one is poisoned. He has 10 slaves to test the wine and a 10-day party. The poison takes effect in exactly 10 days. How can the king find the poisoned wine in time?

Answer: The king uses a binary system to label the bottles and test them on the slaves. Each slave drinks from certain bottles according …

The Monty Hall Problem

Sun, 10 Dec 2023 10:27:24 GMT

The Monty Hall Problem: You're on a game show and given the choice of three doors: Behind one is a car; behind the others, goats. You pick a door, say No. 1, and the host, who knows what's behind the doors, opens another door, say No. 3, revealing a goat. He then asks if you want to switch to door No. 2. Is it to your advantage to switch?

Answer: Yes, sw…

What Comes Once In A Minute, Twice In A Moment, But Never In A Thousand Years?

Sun, 10 Dec 2023 09:27:10 GMT

Answer: The letter 'M'.

The Weighing of Balls

Fri, 08 Dec 2023 16:04:05 GMT

The Weighing of Balls: You have 8 balls identical in size and appearance but 1 is heavier than the others, all of which weigh the same. You have a balance scale that can compare the weight of any two groups of balls. What's the minimum number of weighings needed to find the heavier ball?

Answer: Two weighings. First, weigh 3 balls against 3 others. If th…

What five-letter word becomes shorter when you add two letters to it?

Fri, 08 Dec 2023 12:21:21 GMT

Answer: SHORT (add 'ER' to make SHORTER).

The Coin Triangle

Thu, 07 Dec 2023 11:24:05 GMT

The Coin Triangle: Flip the triangle. You have a triangle made of 10 coins arranged in 4 rows. Move only three coins to flip the triangle upside down.

Answer: Move the coins from the left side of the bottom row to form the new apex of the triangle, and adjust the two rightmost coins from the same row to complete the sides.