Day after day, the letters flooded into Parade magazine's offices. First there were dozens; then hundreds. Finally, there were over 10,000. All of them were addressed to Marilyn vos Savant, and almost all said the same thing - that she had made a stupid mistake in answering a probability problem. "Maybe women look at maths problems differently than men," said one pityingly.

In fact Vos Savant had got the answer right. But it took a very long time to convince her critics.

She was born in St Louis, MissouriA state in the Midwestern region of the United States. in 1946. At 10, she took an intelligence test which found that she had a mental age of 23. As an adult she was listed in the Guinness Book of World Records as having the highest IQA means of measuring human intelligence. A person's IQ is usually ascertained by making them sit a standardised test. Some have criticised these tests as a means of evaluating intelligence, claiming that they ignore much of what it means to be intelligent. in the world: 186.

As a result, Parade published an article about her, and invited her to answer some questions from readers. This proved so popular that she was given a regular column. Ask Marilyn is still going 37 years later.

The controversy that engulfed her was about the Monty Hall problem, named after the host of a game show.

Imagine a game show in which you have three doors to choose from. Behind one is a car - your prize if you make the right choice. Behind the other two are goats.

Say you choose door 1. The host leaves it shut and opens door 3, which reveals a goat. He then asks you whether you would like to choose door 2 instead of door 1.

The question for Ask Marilyn was: do you have a better chance of winning if you switch doors? Vos Savant said yes: with door 2 you would have a 2/3 chance of success instead of 1/3.

Most of the mail that followed - some of it from highly distinguished mathematicians - insisted that this was wrong. With two doors left to choose from, they said, the probability must be 50-50. One man accused her of "mathematical illiteracy"; 92% of readers and 65% of academics agreed.

Vos Savant explained that the probability of door 1 being the right choice was 1/3 at the beginning, and nothing that happened afterwards could change that. This meant that once door 3 was eliminated, the odds on door 2 must be 2/3.

Most of her critics eventually accepted her logic, which was confirmed by computer models. A maths professor who had written a letter offering to explain where she had gone wrong sent another to apologise: "I'm now eating humble pieTo admit that one was wrong or accept that one has been defeated. ... It's been an intense professional embarrassment."

His offer would now be described as "mansplaining". This is the phenomenon of a man explaining something to a woman because he assumes he knows more about the subject than she does. Very often, he does not.

The author Rebecca Solnit tells of a man at a party telling her at length about a book she must read. In fact it was a book she had written - and he had not read.

Solnit argues that society encourages men to believe that they have more authority than women - and encourages women to accept this. An experiment at YaleYale University is a private Ivy League research university in New Haven, Connecticut, founded in 1701. found that if a man and a woman applied for a job with identical CVs, the man had a better chance of getting it.

Yes: A word as clumsy as "mansplaining" would not have caught on otherwise. And there are equivalents in many other languages: "mecspliquer" in French and "herrklaren" in German, for example.  

No: They cannot afford to be now that many top positions in politics and elsewhere are occupied by women, and sexism is no longer tolerated in most of the world's leading countries.  

Or... Mansplaining is only possible if the men responsible have an audience - but women are often too polite to shut them up. The problem would disappear if women were less tolerant of such behaviour. 

Missouri - A state in the Midwestern region of the United States.

IQ - A means of measuring human intelligence. A person's IQ is usually ascertained by making them sit a standardised test. Some have criticised these tests as a means of evaluating intelligence, claiming that they ignore much of what it means to be intelligent.

Humble pie - To admit that one was wrong or accept that one has been defeated.

Yale - Yale University is a private Ivy League research university in New Haven, Connecticut, founded in 1701.