作者: richands (湛蓝水色) 看板: GMAT
标题: [计量] JJ 46
时间: Mon Jun 15 15:22:47 2009
Q46: (Lu: This question maintains a water-tight logic!)
The probability that event A will not occur is 0.8. The probability that
event B will not occur is 0.6. The probability that neither event A nor
event B will not occur is 0. What is the probability that one of the two
events of event A and event B will occur?
Answer Choices: 2/5, 3/5, 12/25 …
ANS:3/5
Note from Lu:
From “The probability that neither event A nor event B will not occur is 0.”
→ Neither A nor B will occur = 0.4 → This guarantees that “A Occurs” and
“B Occurs” are two completely separate sets that have no overlapping area.
但CD上有人这样说
A发生= 1 – 0.8 = 0.2
B发生= 0.4 因为AB都不发生的状况不存在，所以AB有交集，
AB = 1/5 * 2/5 = 2/25 A非B非 = 0
所以1 – AB – A非B非 = 23/25
大家觉得是哪个呢？
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◆ From: 163.14.35.108
※ 编辑: richands 来自: 163.14.35.108 (06/15 15:54)
1F：推 blake618:A发生和B发生应该有交集 06/15 16:54