Suppose you are attending a wedding of 50 people, someone may ask, "I wonder what is the probability that two people here are in the same Amanome?" The same here refers to the same Amanome, for example, on May 5th, but it doesn't mean that the birth time is exactly the same. "

Perhaps most people think that this probability is very small, and they may try to calculate it, guessing that this probability may be one in seven. However, the correct answer is that there are about two guests whose birthdays are on the same day attending the wedding. If the birthdays of this group of people are evenly distributed at any time in the calendar, the probability that two people have the same birthday is 97%. In other words, you have to attend 30 parties of this size to find a party without the same birthday.

Step 2 pair socks

The answer to the question how many pairs of socks can be paired is not two. Because on a dark winter morning, if I take out two socks from the drawer, black and blue, they may never be a pair.

In this way, with the help of one more sock, the mathematical rules can overcome Murphy's law. From the above situation, it can be concluded that the answer to "how many socks can make a pair" is three.

Of course, this is only true if the socks are two colors. If there are blue, black and white socks in the drawer, take out a pair of socks with the same color, at least four pairs. If there are 10 pairs of socks with different colors in the drawer, you must take out 1 1 pairs of socks. According to the above situation, the mathematical rule is: If you have n kinds of socks, you must take out N+ 1 to ensure that you have an identical one in Shuang Yi.

It is not the fairest to flip a coin.

Flipping a coin is a common way to make a decision. People think this method is fair to both sides. Because they think that the probability of coins falling backwards is the same as that of coins falling backwards, both of which are 50%. Interestingly, this very popular idea is not correct.

First of all, although it is unlikely that a coin will stand on the ground when it falls, this possibility exists. Secondly, even if this small possibility is ruled out, the test results show that if you flick the coin with your thumb in a conventional way, the probability that the coin will still be up when it hits the ground is about 5 1%.

4, cooking time (mathematician Gu Chaohao's "Life Mathematics")

Take the simplest cooking, we usually wash the bowl first, and then put the fried dishes into the bowl. Gu Chaohao, who knows how to wear an apron, calculated and came to a "conclusion": according to the overall planning method, cooking time should be fried first, and then washing dishes, so that the time for washing dishes is saved.

5, discharge time (mathematician Gu Chaohao's life mathematics)

As soon as he entered the hospital, his liver function index dropped slowly. After several weeks of blood tests, Mr. Gu solemnly said to the nurse, "Can you change the next routine examination to 10 days later?" Because according to the previous test report, I made a prediction, 10 days, my liver function index will fall back to normal. According to the original blood drawing cycle, it will take two weeks to leave the hospital. "A word amused the whole hospital. Sure enough, the patient was discharged from the hospital four days in advance and took less blood.

References:

People's network, interesting mathematics in life: what is the probability of the same Amanome?

People's Daily Online "Life is full of mathematics, and Academician Gu Chaohao adds, subtracts, multiplies and divides all his life"