求解一道prep输血，急！

小目八

In May, Xiang sold 15 used cars. for there 15 cars, the range of the selling price was $15000 and the lowest selling price was $4500. In June, Xiang sold 10 used cars. for there 10 cars, the range of the selling price was $16500 and the lowest selling price was $6100. what was the range of the selling price of the 25 used cars sold by Xiang in May and June.
A. $15600
B. $15750
C. $16820
D. $18100
E. $19200

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答案是D

我主要的问题是看不懂题目在说什么。什么叫the range of the selling prices?

chasingM7

range of selling price = highest price - lowest price.