GWD8数学求解，谢谢

Q9

If an integer n is to be chosen ar random from the integers 1 to 96, inclusive,what is the probability that n(n+1)(n+2) will be divisible by 8?

A1/4

B3/8

C1/2

D5/8

E3/4

At a garage sale, all of the prices of the items sold were difficult. If the price of a radio sold at the garage sale wan both the 15th highest prie and the 20th lowest price among the prices of the items sold,how many items were sold at the garage sale?

A33

B34

C35

D36

E37

1.C   带入尝试，n=2 成立 n=4 成立 n=6 成立 。。。。

假设n=偶数都成立 

证明 设n=2K n=2K相当与n=4T+2或4T-2或4T

当n=4T+2时 原式=（4T+2）（4T+3）（4T+4）=8（2T+1）（4T+3）（T+1）

当n=4T-2时 原式=（4T-2）（4T-1）（4T）=8（2T-1）（4T-1）T

当n=4T时 原式=4T（4T+1）（4T+2)=8T（4T+1）（2T+1）

都可以被8整除

这种题举例子，找sense就选，考试时不必证明。

2。B  34    14个比自己高，19个比自己低，加上自己，就是34