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标题: PREP数学23题的解释错了吧 [打印本页]

作者: 切尔西 时间: 2010-3-23 15:22
标题: PREP数学23题的解释错了吧
23.1653-!-item-!-187;#058&000843

At least 100 students at a certain high school study Japanese. If 4 percent of the students at the school who study French also study Japanese, do more students at the school study French than Japanese?

(1)16 students at the school study both French and Japanese.

(2)10 percent of the students at the school who study Japanese also study French.

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【答案】B

【思路】

	French	~French
JP	a	b
~JP	c	d
			Total:

設study French & study JP 人數為a

設沒有study French & study JP 人數為b

設study French & 沒有study JP 人數為c

設沒有study French & 沒有study JP 人數為d

題目已知
,,,求a+c > a+b ?
(1) a=16, 不充分

(2)
,已知,可算出,可得a+c>a+b,充分

我认为这题应该选D的，条件一中的4%应该是指学法语的人的吧，请牛牛帮忙分析

作者: Antareslrb 时间: 2010-3-23 15:53
lz想得太复杂了
设有J人study JP，F人study French，X人既学JP又学French
由题干中 4 percent of the students at the school who study French also study Japanese 可知：
X=4%*F
由（2）可知：
X=10%*J
所以 4%*F=10%*J，可推得结论

作者: 切尔西 时间: 2010-3-23 20:55
哦，是我错了，看丢了最开始的at least, 晕倒，希望考的时候不要这样

作者: 小鱼good 时间: 2010-3-23 22:55
麻烦吧prep数学发我一下吧，谢谢啦371504723(AT) QQ.C0M

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