扫描二维码，直接登录
题库 / Prep2007E1-DS-183
The positive integers x, y, and z are such that x is a factor of y and y is a factor of z. Is z even?
(1) x is even.
(2) y is even.
Statement (1) ALONE is sufficient, but statement (2) alone is not sufficient.
Statement (2) ALONE is sufficient, but statement (1) alone is not sufficient.
BOTH statements TOGETHER are sufficient, but NEITHER statement ALONE is sufficient.
EACH statement ALONE is sufficient.
Statements (1) and (2) TOGETHER are NOT sufficient.
还没有题目讲解（毕出老师会陆续发布对官方考题的解读，请保持关注）。
Y=AX Z=BY Z=ABX (1)xz是偶数，那么要么 x偶，z偶；要么x奇数z偶数，因为x是z的一个因子，所以如果x是偶数z一定是偶数，这两种情况下不管怎么样z都是偶数 (2)y是z的因子，所以y偶z一定偶
假设X和Y分别是奇数和偶数的情况即可发现，要是XZ为偶，且X为Z因数，X和Y必定同为偶数。