There are 2 stores, Parkinshop and Wellcome, 1 good (apple) and three consumers, Mary, Ann and Susan. Each consumer values an apple $2, i.e. if the price is equal to or less than $2, each consumer will buy exactly 1 unit, and 0 otherwise. The marginal costs of an apple to the stores are $0.5 and there is no fixed cost. Mary always buys from Parkinshop (if the price is not more expensive than $2) and Ann always buys from Wellcome. Susan is a shopper and always buys from a store which charges a lower price.
Question: What prices do the stores charge in equilibrium? Explain.


市场上有两家超市（1，2），一种商品（苹果）和三个消费者（A,B,C）.当苹果价格等于或小于2元时，三个消费者都会买苹果，否则都不买。每个苹果边际成本是0.5元，没有固定成本。
A只会在超市1买，B只会在超市2买，C在便宜点的那家超市买。

问：均衡时超市的价格是怎样？

（我做出来总是有些模棱两可，需要讨论几种不同情况么？麻烦各位帮帮忙！感激不尽！！）