作者duwaptt (uu)
看板GRE_Verbal
标题请问数学题目
时间Fri Sep 14 17:52:44 2007
In a graduating class of 236 students, 142 took algebra and 121 took chemistry.
What is the greatest number of students that could have taken both algebra and
chemistry?
A:21 B:27 C:37 D:121 E:142
答案是D 我想好久都想不出来 麻烦高手指导 谢谢
我是想 142 +121=263 263-236= 27 但是不对 哀
2. If 55 percent of a group of people have brown hair and 80 percent of the
same group do not have red hair, what fraction of those who do not have brown
hair have red hair? 答案是5/9
真的想不出来!
3 一个数学观念: 一个圆 以直径当成内接三角形的底 以圆上任一点画个三角形
会因为底边都一样长 而造成顶角(圆上的角)度数一样吗??
4 N= (K+R/S)/(t/v) In the equation above K, R, S, t and v represent positive
numbers. Multiplying which one of these numbers by 2 will reduce the value of
N to 1/2 of its present value?
答案是t 不过将S变两倍 好像也可以使N变1/2 ??
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※ 发信站: 批踢踢实业坊(ptt.cc)
◆ From: 59.104.172.241
1F：推 gts:1.他没有说代数课跟化学课是同一时间阿!所以上 59.117.163.104 09/14 18:11
2F：→ gts:化学课的人可以上代数课!取比较小那一个! 59.117.163.104 09/14 18:12
3F：推 gts:3.圆周角的角度 = 所对弧的角度的1/2, 59.117.163.104 09/14 18:19
4F：→ gts:所以一圆直径为斜边内接三角形为直角三角形 59.117.163.104 09/14 18:19
5F：推 eadanlin:第二题我怎麽算4/9 QQ 140.113.92.6 09/14 18:48
6F：推 eadanlin:第四题S*2且K/2才能使N减半 140.113.92.6 09/14 18:51
7F：推 kgc:2.55%的人是棕发, 80%的人不是红发, 问不是棕븠 58.99.17.52 09/14 19:00
8F：→ kgc:发的人中 是红发的机率? 58.99.17.52 09/14 19:00
9F：→ kgc:这是条件机率 应该4/9 58.99.17.52 09/14 19:00
10F：推 niwhu:第二题是问fraction喔...不是机率 140.109.66.205 09/14 19:36
11F：推 niwhu:非红发的包含了棕发的集合，换言之非棕发的ꐠ 140.109.66.205 09/14 19:40
12F：→ niwhu:包含红发的集合 140.109.66.205 09/14 19:42
13F：推 niwhu:fraction是机率啦(sorry上面当我没讲) 140.109.66.205 09/14 19:45
14F：推 duwaptt:sorry 第2题是4/9才对 59.104.172.241 09/14 19:57
15F：→ duwaptt:不过 第二题 能否提供算式 我不会列式 59.104.172.241 09/14 19:58
16F：推 niwhu:0.2/0.45 140.109.66.205 09/14 20:11
17F：推 duwaptt:谢谢 59.104.172.241 09/14 20:14