Miss the weather next door

First of all, clarify the relationship between merchants and neighbors. The merchant exchanged 100 pieces of fake money from the customer for 100 pieces of change from the neighbor (there was no fake money in the change), but afterwards the neighbor found that the 100 pieces given by the merchant were fake, so the merchant paid the neighbor 100 pieces, so the neighbor and the merchant actually had no extra money to trade. Next, let's talk about the customers and the merchants who sell shoes. They originally lost 15, but also because of the fake money given by customers. Because the customer took the shoes, 30 pairs of shoes add up to * * which is15+70+30 =115.