How to calculate the interest of the bidding meeting

Folk bidding committees widely exist in the southeast coastal provinces of China with a long history. What kind of organization is the bidding meeting? Why would someone spontaneously organize a bidding meeting? Generally speaking, private bidding will adopt cash operation mode. Although there are various names and specific practices, they are essentially interest-bearing loans between members. The sponsor of the bidding meeting is generally called the meeting head, and the ordinary members are called the meeting feet. At the beginning of the meeting, the person in charge called the club together and agreed whether the principal scale of the club should be 100 yuan or 1000 yuan, 10000 yuan and so on. , respectively, known as the hundred yuan club, thousand yuan club and ten thousand yuan club. Hundred yuan club means that the principal paid by each club foot is 100 yuan each time. In the way of using the bidding fund, if all members are agreed to pay the same interest, it is called "flat meeting", and if bidding is adopted, it is called "bidding meeting". In the organization and use cycle of funds, if it is agreed to use funds once a month and pay the principal, this is called "monthly meeting". The bimonthly meeting, the ten-day meeting, the ten-day meeting and the daily meeting are all understood in this way. They are all "done" through bidding. Take 10 people as an example. At the first bid opening, 10 participants paid RMB 100 respectively, which was kept by the meeting leader. On the day of bid opening, each meeting foot privately wrote an interest standard on the note, which was opened by the meeting head in public. If the person who writes 30 yuan's interest is the highest among 10 members, then he will win the bid, and he can take away all the 1000 yuan membership fees paid by his * * * 100 members on the spot, and the "moment" will be over. According to the operation flow of the bidding meeting, each club can only bid once, and the promised interest will be added when paying the membership fee next time after winning the bid. In this way, the first successful bidder has to pay 9 times the interest, the second successful bidder only needs to pay 8 times, and so on. By the end of the meeting, he had paid off the main arrears for nine months on time. At this time, there was no bidder, so he naturally won the bid, and got back the 900 yuan membership fee paid by the previous nine clubs and the interest they promised at one time, which was equivalent to lump sum deposit. The first person has to repay his winning 900 yuan membership fee in installments within 9 months, and pay 270 yuan interest, which is equivalent to loan installment repayment. It stands to reason that no one will do such a loss-making thing. Then, why are there people who are keen to participate in the bidding meeting? Because the tenth one will make money, because he doesn't bid, so he doesn't have to pay interest. According to the operation flow of the bidding meeting, the promised interest will be added to the next payment of membership fees after each club wins the bid. Or take 10 people as an example. Each club has to pay 10 times the membership fee 100 yuan, but the first club that wins the bid has to pay 9 times the interest; The second winning bidder will pay 8 times interest after winning the bid. By analogy, the 900 yuan membership fee paid by the last club and the first nine clubs and their promised interest can be obtained directly without bidding. The less times the winning bidder pays interest, the more interest he gets. The last club foot doesn't have to pay interest, but it gets the interest paid by all the clubs in front, and it only earns no compensation. What if everyone wants to be the last one? Meeting leaders will draw lots, Monday, Tuesday and Wednesday, and so on. It seems that the leaders attending the meeting have taken great pains to ensure the normal progress of the bidding meeting. If we operate according to this rule, a bidding meeting will inevitably be that the first successful bidder loses money, and then the successful bidder makes money. As for how much to lose and how much to earn, it depends on the interest promised when winning the bid. Take 10 people as an example. If each successful bidder wins the bid with interest of 3 points, that is, pays the principal of 100 yuan at 30 yuan interest every month, then the first successful bidder will repay the 900 yuan membership fee in installments within 9 months, and pay 270 yuan interest, which is equivalent to the installment repayment of the loan with a monthly interest rate of 3.33%. Between the first successful bidder and the last successful bidder, the interest expense decreases and the interest income increases. At the last meeting, he paid nine months' membership dues on time, and got a reward. He got 900 yuan back in one lump sum, and got the interest 270 yuan paid by other meeting feet, which was equivalent to lump sum deposit and withdrawal, and the monthly interest rate was 3.33%. This interest rate is much higher than the bank interest rate. This is illegal.