作者PINKENVI (勿忘初衷)
看板GMAT
标题[计量] GWD 23-16 和 GWD 23-25
时间Mon Dec 17 15:05:55 2007
Q16:
If k is a positive integer, what is the remainder when 2^k is divided by 10 ?
(1) k is divisible by 10.
(2) k is divisible by 4.
Answer: B
这题我不太知道怎麽算!
Q25:
Of the high school students who participated in a recent survey,
110 had taken a course in biology and 230 had taken a course in history.
How many students participated in the survey?
(1)Of the students who participated in the survey, 120 had taken neither a course in biology nor a course in history.
(2)Of the students who participated in the survey, 60 had taken both a course in biology and a course in history.
Answer:C
这题为啥是C阿!如果已经个别知道biology和history的人数!又只要知道他们重复的人数!
那不就是用P(AUB)=P(A)+P(B)-P(A交集B)就可算出嘛?
我不懂为啥还要用到(1)?
嗯 谢谢回答! :)
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