Goldbach conjecture Goldbach conjecture 1742 On June 7th, German amateur mathematician Goldbach wrote to the great mathematician Euler at that time and put forward the following conjecture:

(a) any n? 0? The even number of 6 6 can be expressed as the sum of two odd prime numbers.

(b) any n? 0? The odd number of 6 9 can be expressed as the sum of three odd prime numbers.

This is the famous Goldbach conjecture. Since Fermat put forward this conjecture, many mathematicians have been trying to conquer it, but they have not succeeded. Where the hell is the money? Three people go for 30 yuan a night. They each paid 10 yuan to make a 30 yuan and gave it to the boss. Later, the boss said that 25 yuan was enough for today's discount, so he took out the 5 yuan and asked the waiter to return it to them. The waiter secretly hid 2 yuan's money, and then distributed the rest of 3 yuan's money to three people, each 10 yuan. In this way, everyone handed in 10 yuan at the beginning. Now it's back to 1 yuan, that is, 10- 1=9, each person only spent 9 yuan money, three people each 9 yuan, 3×9 = 27 yuan+2 yuan hidden by the waiter =29 yuan, where is the one yuan left? Five fruits that can be used at one time are "24" -2 cubes with small 5+(-4) times the square of (-2 times 1)-12 times (-15+2 with small 4). You can buy a drink, and two empty cups can be exchanged for one drink. There is a train carrying 38 sheep, 47 cows, 69 rabbits and 72 pigs. How old is the driver of this train? A man bought a chicken for 8 yuan and sold it for 9 yuan.

Then he thought it was not cost-effective, 10 yuan bought it back. 1 1 sell it to another person and let him make money.

How much did it cost?