Required Mathematical Intelligence

Chapter 64 Carrie and Jenny

"There's a snake in my bedroom!"

"Come on, the kitchen is on fire!"

"Sissy, your child has crashed into a car, go to the city center hospital!"

Don't panic, none of this may be true.In fact, if it happens to be April 4 and you live in the UK, then it's almost certain that none of them are true.Because on "April Fool's Day", they will joke with you and play tricks on you!
This custom originated in an unfortunate incident in 1545.A Norwegian scientist named Luf Lilbo, who was living in England at the time, was trying to unravel the mysteries of flight.

The scientist's behavior was a bit eccentric, but he was undeniably smart.It appears that his flying experiments were successful, as King Henry VIII received a letter from Mr. Lilbo.In the letter, Mr. Lilbo claimed that he had uncovered the secret of flying, and respectfully invited the king to visit Westminster Abbey on April 4 to watch his air show.

So, on April 4st, the king and important political figures stood in the square outside Westminster Abbey, waiting for Mr. Lilbo to fly through the air.However, they saw nothing.Lilbo didn't mean to be joking, what he said in the letter was actually the truth.He had already mastered the knack of flying, and the reason he was not shown at Westminster Abbey was that his flying machine had malfunctioned and crashed into a tree, killing himself.This is a tragedy in the history of technology.

Since then, Britain has formed a custom to set April 4st as "April Fool's Day".On this day, people often tease each other by telling lies.

For more than 400 years, this ancient custom has persisted, so that prisoners in custody are also allowed to play "April Fool's Day" tricks.

Most of the prisoners held in the "jungle" prison have relatively minor crimes.Sisters Carrie and Jenny, one arrested for stealing goods from a supermarket, and the other detained for taking drugs, happened to be locked in the same cell.On April Fool's Day, the two sisters made an agreement: sister Carrie told the truth in the morning and told lies in the afternoon; sister Jenny told lies in the morning and told the truth in the afternoon.

Sisters Carrie and Jenny look exactly alike, but there is a slight difference in height. It is almost impossible to tell who is the older sister and who is the younger sister.So when the prison guards came into the cell to interrogate Carrie, he was also confused.But he knew the agreement between the sisters on this day.

He asked, "Which one of you is Carrie?" "It's me!" replied the taller one. "It's me!" The shorter one replied in the same way.The guard was even more confused.After thinking about it for a while, he asked a question: "What time is it?" The taller one replied, "It's almost 12 noon." The shorter one replied, "It's past 12 o'clock." .” Based on the answers of the two, the smart guard immediately deduced which one was Jiali.

May I ask: Do the guards go to the cell in the morning or in the afternoon?Is the taller Carrie, or Jenny?
[Answer: In the morning, the taller one was my sister Carrie.

We can use the hypothesis method to solve this problem.

Suppose: It was afternoon.

If it was afternoon, Carrie was telling lies and Jenny was telling the truth, so when the guard asked "Which one of you is Carrie", the taller or shorter would say "It's not me", And they both said "it's me".It can be seen that it was not afternoon, but morning.

Since it was morning, the answer "it's almost noon" is the truth, that is, the taller one told the truth; "and the morning has passed" is a lie, that is, the shorter one It is a lie.Since it is known that Carrie is the one who tells the truth in the morning and Jenny is the one who tells the lie, the taller one is Carrie and the shorter one is Jenny. ]
(End of this chapter)