in my , xiang sold 15 used cars . for these 15 used cars the range of selling prices was 15000 and the lowest selling price was 4500 . in june , xiang sold 10 cars . for these 10 cars the range of selling was 16000 and the lowest selling price was 5000 . what was the range of selling prices for the 25 used car sold by xiang in may and june ?