1。Last month, 15 homes were sold in town X. The average sale price of the homes was 150000 and the median sales price was 130000. which of the following statements must be true?
1 at least one of the homes was sold for more than 165000.
2 at least one of the homes was sold for more than 130000 and less than 150000.
3 at least one of the homes was sold for less than 130000.
A 1 only
B 2 only
C 3 only
D 1 and 2
E 1 and 3 此题选A，请问思路？
2 A centain law firm consist of 4 senior partners and 6 junor partners. How many different groups of 3 partners can be formed in which at least one member of the group is a senior partner?(Two groups are considered different if at least one group member is different.)
A 48
B 100
C 120
D 288
E 600
此题选 B。我算的是C 41 * C 92 = 144。 3。On a certain sight-seeing tour, the ratio of the number of women to the number of children was 5 to 2. What was the number of men on the sight-seeing tour?
条件1 On the sight-seeing tour, the ration of the number of children to the number of men was 5 to 11.
条件2 The number of women on the sight-seeing tour was less than 30.
答案是C。请问条件2less than 30也能算出结果吗？ 4 In the xy-plane, what is the y-intercept of line L?
条件1 The slope of line L is 3 times its y-intercept.
条件2 The x-intercept of line L is -1/3. 此题选什么呢？ 请高手请教！！！多谢。 | 
