Xiao Zhang is the boss who sells shoes. A pair of shoes were purchased in 20 yuan and sold in 30 yuan. The guest gave 50 yuan, and Xiao Zhang had no change, so he took this 50 yuan to his neighbor and changed it into 5 pieces 10, and found 20 yuan for the guest. Later, neighbors found out that 50 yuan was counterfeit, so Xiao Zhang had to pay for it to his neighbor 50 yuan. How much did Xiao Zhang lose?

I think if we don't admit that 50 yuan can still circulate, we will lose 90%, and if the People's Bank of China agrees, we will lose 40%.

The explanation is as follows:

Those who cashed in gave counterfeit money to 50 yuan, and the mentally retarded boss really gave Erhuo and his neighbors five real coins 10 yuan.

50 (fake) -> 5X 10 (real money)

The cash given by the mentally retarded boss is real money from 20 yuan and real money from 30 yuan. At this time, the mentally retarded boss has lost the real money in 20 yuan, so there is no question of talking about shoes here. Suddenly, the neighbors of these two goods found out, oh, my God, this TM is fake money, so they came to look for it. You have to pay him back 50 pieces of real money. Of course, it's still your business. Counting the real 30 yuan coins left in your hand just now, you have to take out the real 20 yuan coins from your pocket again, because 20 yuan just cashed them. This lost another 20 yuan.

Remember at this time, damn it, those shoes are also for people. According to the purchase price of 20, you gave 20 yuan away for nothing. What is said here is a net loss, so it is 20. You can't treat the money you want to earn as a loss, can you? You have to sell this pair of shoes for 10 thousand, which is a big loss

And the 30 yuan in your hand just now, 10 yuan's profit is not to mention. You know, the retarded boss is not interested in this deal at all. He bought and sold his neighbors' real money with two goods, and traded 20 yuan for his shoes, making a profit 10 yuan, but 10 yuan's real money also belonged to the neighbors of the two goods, so he had to pay it back. You can't say that I have 10 yuan's profit here, just take 40 as 50 and give it back to others. So this 30 yuan (including 10 yuan's profit) belongs to those two commodities.

Now calculate:

20 yuan's cash +20 yuan's own pocket +20 yuan's shoes +30 yuan's money that has nothing to do with you =90 yuan's loss of being fooled. Thank you ~ ~!