How to choose a good wife: a mathematical problem
by Baigalmaa staff
How to choose a good wife: a mathematical problem
In 1611, Johann Kepler, the great astronomer, discoverer of the laws of motion of the stars, mathematician and genius scientist, after his wife Barbara passed away, he decided to get a wife in order to have two children and a house. chose one of the women to marry.

Because of his natural tendency to point things out, he met with each person and talked to them, which was recorded in his diary and shared with the public by Alex Bellos in his book "Mathematics of Vinogradin". Johann Kepler described these women who wanted to win his heart: ""the first woman, she had a bad breath", "the second woman, she likes too much jewelry and luxury, it will not be good", "the third woman, the husband in front of her is an easy fate "I don't expect to show", "the fourth woman is an insatiably beautiful woman, but I want to meet the fifth". At this time, while some time passed in disbelief and doubt that his circle praised him as "the fifth woman, modest, hardworking, and a good stepmother", women #4 and #5 impatiently attracted the heart of this great astronomer. was eliminated from the competition. Poor Johann began to meet the next women. He was afraid of the sixth woman, and she said, "I can't afford her expenses because she is of high birth and nobility", "the seventh woman is nice, but I want to meet the next women", "the eighth one, I didn't like it", "the ninth one, bad", "tenth, not suitable for anyone", "tenth, too young", and it is said that no one was selected, considering that it was a waste of time. Alex Bellos, in his book, took this event as an example of how Johann Kepler, at the time, needed an optimistic strategy that focused on increasing the probability of satisfaction, not the probability of success. This strategy, which helps to choose anything, is very simple, carefully thought out and listed, and shows the alternative or the following method, which is satisfactory for mathematicians and rarely leads to bad results, although not always good results. In 1960, this method was called "a la Kepler" and later it was called "Specific Selection Problem". The method is to meet and discuss with all 20 people on the recruitment list. If you meet all of them, you have to choose the last one because you haven't selected the others, so that person will be given the job. Or, when you go back and choose from the first people, it is possible that they have another job, and they solve the problems that lead to doubts. In 1960, Martin Gardner formulated this method, (previously partially studied by other mathematicians) and concluded that it is correct to choose from the first 36.8% of all people on a given list, or job, or whatever. Why 36.8%? you will surely ask. Mathematicians call it the *e* number (=2,718 281 828 459 045 235 360 287 471 352 662 50): it is related to the percentage of 1/e which is 0.368 or 36.8. This formula has been proven to be applicable to all types of screening and although it does not promise absolute results, it is said to bring a guaranteed success rate of 36.8%. This is considered a good indicator.

Alex Bellos, poor Johann, wrote at the end of his thread that if he had used this formula, he would have chosen #4 from 36.8% of the 11 participants and lived happily ever after without hesitation and unpleasant subsequent meetings.