The Lady and the Tiger.

Let's solve Jerome's favorite puzzle  from the Raymond Smullyan's book "The Lady and The Tiger."
This puzzle originates from a short story published in the 1882!  In this story a king of an ancient land discovers that his daughter has taken a lover far beneath her status. He is deciding to punish this man and teach his daughter a lesson.  So, the king places his daughter's lover in the arena with two draped doors. Behind one door is a simple woman whom the lover must marry if he opens this door, behind the second door is a tiger that will eat the man alive if this door is opened. The princess may use her powers to find out where is the tiger and where is the maiden but will she save her lover and give him to someone else? Can the lover trust the princess?

Our puzzle is less sentimental and cruel. You are standing in front of three rooms and must choose one. In one room is a Lady (whom you could and wish to marry), in the other two rooms are tigers (that if you choose either of these rooms, the tiger invites you to breakfast – the problem is that you are the main course). Your job is to choose the room with the Lady. The signs on the doors are

1. A Tiger is in this room
2. A Lady is in this room
3. A Tiger is in room two

At most only 1 statement is true. Where’s the Lady?

Your answers are accepted any time until midnight Eastern Time on Sunday, on our Family Puzzle Marathon.

Top image by Lal Beral, distributed under CCL.

Red Lights Puzzle

Does it ever happen to you - a week with no inspiration? Your baby is sick, your older kids are on vacation and require entertainment and it is very hot and humid outside. Well, this is my excuse for skipping last week's puzzle. But just as the week ended I went to see a movie with my husband, and here it was - a puzzle in a movie. The movie, Red Lights, is masterfully done and acted, and keeps you in a constant suspense. But then, just as you expect an original resolution, it flops and disappointingly ends leaving some ends loose.

You can skip the movie, but solve this movie's puzzle:

Robert DeNiro's character is a legendary blind psychic that agrees to be subjected to scientific tests verifying his paranormal capabilities. In one of the tests he has to guess random numbers picked up by an independent person behind the wall by reading his mind.  The person picks a number between 1 and 12 and signals the psychic that a number is chosen.  The psychic attempts to guess what number it is. Then the experiment repeated in the same manner.  The psychic was able to guess those numbers with a very high success rate, much higher than chance. Is he really capable of mind reading? When we and the scientists view experiment's videotapes we can see that psychic makes a key comment about his watch and asks scientists (that are inspecting the watch for fraud) to be very careful with its gentle hands. How can the watch be used by the psychic to fool everyone in this experiment without any obvious fraud?

Your answers are accepted any time until midnight Eastern Time on Sunday, on our Family Puzzle Marathon.

Image by Artnow314, distributed under CCL.

First Assignment

This puzzle is celebrating our master solver Wang who recently turned his 20th puzzle.

Government of Canada (where Wang lives) observed his brilliant puzzle solving skills and hired him to join the Canadian Security Intelligence Service. It is so cold up there that even terrorists are trying their best to avoid this country. So, CSIS is busy monitoring the drug dealers. On his first assignment, Wang has bee sent to arrest a man living in an apartment 4A on the PrairieDog street. Neighbor pointed Wang to the apartment where the man and his wife live and warned that it is hard to tell who is who. Upon entering the apartment, Wang confronted two people. Both had long hair, ruggy clothes and were of unclear gender. "Who is the man in this house?" asked Wang authoritatively.
"I'm a woman," said the person on his left.
"I'm not a woman," said the person on his right.
The super new static lie detector in Wang's pocket beeped signifying that at least someone here is lying. Whom do you think he should arrest?

Answers accepted all day long on Friday, on our Family Puzzle Marathon. They will be hidden until Saturday morning (EST) and everyone who provided a correct solution will get a puzzle point.

The Thieving Clown

The trainee clowns at Bozo College are in a state of shock. A thief has deprived the college of 873 yellow balloons and a broken-down balloon pump. Happily, there was a witness to the crime, who was stated that the thief was wearing the College's clown uniform and had a red nose. Previous research has shown that on 80 percent of occasions witnesses will correctly identify the color of the nose of a clown involved in committing a crime. It is also known that 85 percent of the clowns at Bozo College have blue noses and that 15 percent have red noses. What is the probability that the thief had a red nose (assuming that the witness it telling the truth about what he thinks he saw)?

This puzzle is from the great new book by J. Stangroom "Einstein's riddle" that is listed on our Math Resources page.

Submit your answer on our Family Puzzle Marathon Be first to solve three puzzles and get a prize!

The Case of the Arctic Hero

Young man has been trying to impress his dancing partner at the high school prom. He told her about his father who participated in the Arctic Expedition. One winter day his father found himself on a piece of ice that broke loose and was drifting out to sea. He quickly realized that he and the his dogs would freeze out to death unless he started a fire. Alas, he had used up all of his matches. So, he got out a small magnifying glass from his instrument kit and, tearing off sheets from his Arctic Guide book, laid them on a steel instrument box. By focusing the sun's rays through the glass onto the paper, he started a hearty blaze. Fortunately, an ice cutter picked him and the dogs up after 24 hours. Young man was obviously very proud of his father, but the girl - his dancing partner - was rather suspicious. Why?

Submit your answer on our Family Puzzle Marathon Be first to solve three puzzles and get a prize!

This great puzzle is one of the Two-Minute Mysteries from D. J. Sobol book.

Who ate the cake? Who? Who?

One of you two, out there, ate the last piece of cake we were hoping to save for grandma. I can figure out who did it without even checking your sticky fingers and dirty teeth. Whoever did it, pick any odd number. Whoever didn't do it, pick any even number. But be honest! Now, you, standing closer to me, multiply your number by 2. The other person - multiply your number by 3. Share your numbers with each other and tell me their sum. As soon as I hear this sum, I can now figure out who ate the cake! How?

(this puzzle is inspired by a story from B. Kordemsky book)

Submit your answer on our Family Puzzle Marathon Be first to solve three puzzles and get a prize!

White House Party Crashers

A couple from Virginia breezed through the White House security and leisurely enjoyed the State Dinner with the president, vice-president, Indian Prime Minister and an array of other hand-picked guests. All is well, except that the couple has not even been invited to this dinner... Wow!
How did they do it? Rumor has it that the secret service agent asked them "Have you been invited?" They answered: "Yes!" and walked right in. While the Secret Service is trying to figure out how they let it happen, I suggest we help them with some logic. Our world consists of liars and truth tellers. The liars got entangled in their lies so deeply that they always lie, and the truth tellers are always honest. Both, liars and truth tellers, are occasionally being invited to White House parties. And both, liars and truth tellers, may occasionally have an impulse to attempt to crash a White House party uninvited. What question you suggest Secret Service agents ask any party goer, in order to let through only those invited, be it a liar or a truth teller?



(this puzzle is inspired by Giovanni Ciriani's answer to one of our recent puzzles)

To get a correct answer point, please explain your answer on our Family Puzzle Marathon site. Solve three puzzles and get a prize!

Whom To Trust?

You invite two gardeners for a price estimation on picking up all the autumn leaves in your yard. You neighbor, seeing you with them outside, smiles and trying to be polite but still helpful, tells that one of these gardeners is a liar and another is truthful. Hearing this, one gardener says, "I am a truthful one, he is a liar." The second gardener replies, "Yes, he is telling the truth about being truthful, but I am not a liar." Which one is which and why? (this puzzle is adopted from The Super Smart Super Puzzle Book #2 by A. Salny)

Submit your answer on our Family Puzzle Marathon site. Solve three puzzles and get a prize!

A Great Detective Puzzle

The Great Detective, a well-know puzzle solver Rachel T, was investigating a murder. The millionaire had died mysteriously, and his nephew, the chief suspect, had now come up with a will dated only a week earlier, which left everything to him. The Great Detective asked, "And just where did you find this new will?"
The nephew replied, "I was sitting in the library, mourning my uncle, when I noticed on his desk a book opened facedown. I picked it up and there, between pages three and four, was this new will. He must have had written the will, had it witnessed by two strangers so that nobody would know, and been murdered shortly thereafter."

"Arrest that man immediately," said the Great Detective Rachel T. How did she know the story wasn't true? (this puzzle is from the book by Abbie Salny)


Submit your answer on our Family Puzzle Marathon site. Solve three puzzles and get a prize!

Job Interview

You are interviewing two job candidates in a row. First of them admits to you that he has heard how second candidate admitted to him in the waiting room that she is a liar. Can this first candidate be trusted?
Assume that everyone in this story is either chronic liar or truthteller.
(from the Mensa Genius Quiz Book 2)

Cheating

My husband spent last night with his only brother's wife's only brother-in-law's wife. What shall I do to him?