SAT数学概率题

对SAT数学概率题来说，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数学难题中的数学概率题论部分的常用解题技巧进行总结。

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

比较题目：(2)In the integer 3589 the digits are alldifferent and increase from left to right. How manyintegers between 30000 and 50000 have digits thatare 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 manypositive 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, andn=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 hegets b points, what is the probability a/b1?

比较题目：(6)If someone throws a dice twice, what is the probability that the point he getson one throw is bigger than the other?