Is xy > 5 ?
(1) 1 ≤ x ≤ 3 and 2 ≤ y ≤ 4.
(2) x + y = 5
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.
题目分析:
(1) 例如x=1,y=4,满足条件1,但xy=4<5。又如x=3,y=2,满足条件1,但xy=6>5。所以无法确定是否有xy > 5。
(2) 满足x+y的x和y有很多,并不能确定是否有xy>5。
结合条件1和条件2,条件1解析中的两个例子既满足条件1又满足条件2,但无法确定是否有xy > 5。
因此,本题答案为(E),两个条件结合起来也不能解题,必须提供新数据。
我真是over complicated了这道题。。。还做了y=5-x跟y=5/x的曲线.....( ╯□╰ )
6/5 19/5