SAT数学“概率论”部分难题选讲

　　SAT数学对中国学生确实是比较简单的一项，而且SAT拿满分也是比较容易的。但是SAT数学部分却总不能如愿的拿到满分，究其原因，除了英文环境下题目理解错误之外，还有一点就是国内高中学到的解题技巧都没有积极应用，所以导致了解题繁琐，不但浪费了时间，而且还使得答案错误。各位考生一定要注意，对SAT数学来说，你用的方法越简单，你做对的概率越大，而且还可以在考场上省出很多时间来做更有意义的事情。

　　下面我们就对SAT数学概率论部分的常用解题技巧进行总结，以期事半功倍：

　　(1)In the integer 3589 the digits are all different and increase from left to right. How many integers between 4000 and 5000 have digits that are all different and that increased from left to right?

　　比较题目：

　　(2)In the integer 3589 the digits are all different and increase from left to right. How many integers between 30000 and 50000 have digits that are all different and that increased from left to right?

　　(3)If p, r, m are three different prime numbers greater than 2, and n=p*r* m, how many positive factors, including 1 and n, does n have?

　　比较题目：

　　(4)If p, r, m, n, t and s are six different prime numbers greater than 2, and n=p*r*s*m*n*t, how many positive factors, including 1 and n, does n have?

　　(5)If someone throws a dice twice, on the first time he gets a points, and on the second he gets b points, what is the probability a/b>1?

　　比较题目：

　　(6)If someone throws a dice twice, what is the probability that the point he gets on one throw is bigger than the other?

　　(7) Mr. Jones must choose 4 of the following 5 flavors of jellybean: apple, berry, coconut, kumquat, and lemon, How many different combinations of flavors can Mr. Jones choose?

　　总之，做SAT数学在读懂题目的基础上，一定要使用简单的方法来做!