genre_wu

8． F（X）=X^3, 问f(x+1)-f(x) ? 答案2f(x) My answer: 3x^2+3x+1 36.W, X, Y, Z是一维数轴上的4个点，W*X*Y*Z>0 ? (1)W*Z<0; (2)W*Y>0 选C My answer: E 40.what's the mean of something per month? A. there is 6,000 for each of the first six month. B. the total number this year is 54,000 (not sure about the number, but it is larger than 2 times of 6x6000) my answer is 3. My answer: D The rest is same. Thanks for your effort. BTW, I found that there's a quite old JJ. But no one describe it acuratelly and completely. Here it is: 一群用于迁徙研究的鹅中雄鹅占30%，有一些鹅是迁徙的，在那些迁徙的鹅中雄鹅占20%，问雄鹅的迁徙比例和雌鹅的迁徙比例的ratio。给出定义：某一性别鹅的迁徙比例=某一性别鹅中迁徙的数目/某一性别鹅的数目 My answer: 7/12

[此贴子已经被作者于2003-1-29 0:22:01编辑过]

nobodytest

65.集合S五个连续整数，集合T七个连续整数，问s和t的median是否相等。
1）集合S的median是0
2）两个集合中所有数的总和是一样的。
题目如此，请讨论。我好像选的是B
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[确认]B 因为S={S-2 , S-1 ,S, S+1 ,S+2}
T={T-3, T-2 ,T-1 ,T ,T+1, T+2, T+3}
如果总和一样, S=T
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***Quote koujunyi's words:
我认为这题答案应是C。
在2）中设两个集合中数为X和Y，则（X-2）+（X-1）+X+（X+1）+（X+2）=（Y-3）+（Y-2）+（Y-1）+Y+（Y+1）+（Y+2）+（Y+3），推出5X=7Y，可看出X至少可等于0，7；Y至少可等于0，5。所以只有1）和2）两个条件才能确定中数为0。
不知大家怎么看的？

lisaislisa

to nobodytest , you win ^^

nobodytest

not me,koujunyi does. thanx for your summary
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99、10^n是1到24这些连续整数乘机的最大因子，求n。老JJ
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5
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My: 4
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Open to discuss

littlegal

102、3个硬币是同一面的POSSIBILITY？老jj:1/4
[确认](1/2)*(1/2)*(1/2)*2


Hi, anyone can help me with this question?

Why we haev to times 2??????

uzhany

Littlegal,

you need to time it by 2 b/c you have to account for the head and tail.  
(1/2)(1/2)(1/2) only for heads, then you need times two to include the tail

uzhany

.11段时间.interview 7 个人,有多少种排法

is it P(7 11)?

littlegal

Uzhany, Thank you for  your help!

5 interviewrs, the manager has 12 different time intervals, 有多少种排法 ??

Is it 12 x 11 x 10 x 9 x 8 ?????

joywzy

能否讲讲12， 14的思路？

lisaislisa

12 组合：从6人中选3人与从5人中选3人的不同组合数？C（3，6）-C（3，5）=10
[确认]
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就是两个组合的差

14 DS：ACCOUNT里有20，000道，QUARTERLY复利。问第一季度的INTEREST？
1） 第二季度的利息比第一的多1%；2）第二季度的利息比第一的多2刀 ==》D
[确认]
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复利公式 A(n+1)=An(1+r)^(n+1)
A1(1+r)-A1 is the interest gained during the first quarter ,set as I1
A2(1+r)^2-A2 is the interest gianed during the second quarter , set as I2
since A2=A1(1+r)
1)=> (I2-I1)/I1=1% and, as we've learn A1 , we can get the only unknow number , the r ( interst )
2) and 1) are essentially the same

^^