Problem Solving

In May, Xiang sold 15 used cars. For these 15 cars, the range of the selling prices was $15,000 and the lowest selling price was $4500. In June, Xiang sold 10 used cars. For these 10 cars, the range of the selling price was $16,500 and the lowest selling price was $6,100. What was the range of the selling prices of the 25 used cars sold by Xiang in May and June?

1) $15, 600
2) $15,750
3) $16, 820
4) $18, 100
5) $19,200

Thanks in advance