请教一个prep的math问题

suzhenbo

题目如下：In a stack of boards at a lumber yard, the 20th board counting from the top of the stack is immediately below the 16th board counting from the bottom of the stack.  How many boards are in the stack?

(A) 38

(B) 36

(C) 35

(D) 34

(E) 32

suzhenbo

还有一道是：For every positive even integer n, the function h(n) is defined to be the product of all the even integers from 2 to n, inclusive.  If p is the smallest prime factor of h(100) + 1, then p is

(A) between 2 and 10

(B) between 10 and 20

(C) between 20 and 30

(D) between 30 and 40

(E) greater than 40

naonao7949

C。E

suzhenbo

  楼上的朋友，可否给出解题的思路？

野田妹

第一個是20+16-1

因為自己被重複算了兩次

suzhenbo

谢谢楼上的，看来第一题我没做好主要是阅读题干时，没有能够理解题意。请问第二题何解？