At a garage sale, all of the prices of the items sold were different. If the price of a radio sold at the garage sale was both the 15th highest price and the 20th lowest price among the prices of the items sold, how many items were sold at the garage sale? 做不出来是因为没看懂吧? 只要意思就是:出售价格不同的一些商品,卖一个收音机的价格在所有商品的价格里是第 十五高,同时是第二十低,问一共有多少商品?不就是把这些东西排队,这个收音机从前 边排第15,从后面数排第20,就是15+20-1=34啊。 |