求教 数学GWD19-36

adasuying2004

Q36:
If x, y, and z are positive integers, is xz even?
(1)      xy is even.
(2)      yz is even.
    
A. Statement (1) ALONE is sufficient, but statement (2) alone is not sufficient.
B. Statement (2) ALONE is sufficient, but statement (1) alone is not sufficient.
C. BOTH statements TOGETHER are sufficient, but NEITHER statement ALONE is sufficient.
D. EACH statement ALONE is sufficient.
E. Statements (1) and (2) TOGETHER are NOT sufficient.
Answer:  E

不是从1，2就能推出3者同号么？为啥不是C？

magi729

不能y是偶数，x,z是奇数么=  =