PP-T2-DS39

[Huang Hsin-Yi]

39. 3150-!-item-!-187;#058&003215
If c and d are integers, is c even?

(1) c(d + 1) is even.

(2) (c + 2)(d + 4) is even.

Ans:C

(1)e*e=e o*e=e
C=e or o............................................insufficient
(2)C+2=e C=e
C+2=o C=o...................................insufficient
(1)(2)結果是一樣, 答案怎會是C勒

[sunnyblue13s]

1.C可能是單數..也可能是雙數
2.C可能是單數..也可能是雙數
1.+2. - 爲了要符合式子....d設為單數....c...一定要是雙數才行.....d設為雙數....c...也一定要是雙數才行....

[Huang Hsin-Yi]

對歐!!