1. In May, A sold 15 used cars. For these 15 used cars, the range of the selling prices was $15,000 and the lowest selling price was $4,500. In June, A sold 10 used cars. For these 10 used cars, the range of the selling prices was $16,500 and the lowest selling price was $6,100. What was the range of the selling price of the 25 used cars sold by A in May and June? (key: 15,600) 这里的range不太理解...
2. In the xy-plane, the line k passes through the origin and through the point (a,b), where ab not=0. Is b positive? (C) 1) the slope of line k is negative 2) a<b
3. Which of the following lists the number of points at which a circle can intersect a triangle? (1,2,3,4,5, and 6) 不太理解1个点怎么截三角？
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发表于 2010-8-30 17:04:43
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