Logic Analysis and reasoning (scammers shopping problems)

Original question:

The cunning swindlers went to the mall to shop and bought 9 yuan worth of money with a nominal value of 100 yuan. The salesman asked him for 91 yuan. At this time, he also said that he had a change, I paid the salesman 9 yuan and paid back my 100 yuan. How much did he cheat the store?

 

Problem Analysis:

First of all, when the scammers took out 100 salespersons and asked him for 91 yuan, the transaction was over. At this time, everything was normal.

When the scammers exchange 9 yuan for their 100 yuan, this is another new transaction (9 yuan for their 100 yuan ).

 

At this time, we can see the two transactions. We can see that the total amount paid by the store is: (91 RMB + goods)

The scammers only pay (9 yuan) in total)

 

In this case, the store is cheated: (91 yuan + goods)-(9 yuan) = (82 yuan + goods)

 

The analysis is complete.

 

There are other analysis methods for your reference.