求助GWD 4-Q9 & Q24

qwrersaa

各位大侠，有谁知道GWD第四套的数学第九题如何解啊？还有第24题我怎么算都应该是多了一元钱（B），是不是答案（C）给错了啊？恳请各位鼎力相助，多谢！

himba

n从1-96随机取，问n*(n+1)*(n+2)能被8整除的概率

当n为偶数的时候，n+2必然也是偶数，而且n和n+2里面至少能有1个能被4整除，所以n取任何偶数都可以。一共有48个

n取奇数的时候，n,n+2都是奇数。n+1是偶数。如果n+1能被8整除，也可以。

7，15，23，31，39，47，55，63，71，79，87，95一共是12个。

总概率就是(48+12)/96=5/8

himba

Q24:

At a certain company, each employee has a salary grade s that is at least 1 and at most 5.

Each employee receives an hourly wage p, in dollars, determined by the formula

p = 9.50 + 0.25(s – 1). An employee with a salary grade of 5 receives how many

more dollars per hour than an employee with a salary grade of 1?

A. $0.50

B. $1.00

C. $1.25

D. $1.50

E. $1.75

这个题之前似乎有讨论。似乎讨论的是B