[計量求解數學

看板GRE作者 (Bonita)時間13年前 (2011/06/08 05:52), 編輯推噓15(15推 0噓 22→)
留言37則, 9人參與, 最新討論串1/2 (看更多)
1.比大小 (ab)^6=b^-4*c^-8 columnA:(ab)^9 columnB:(b^-2*c^-4)^3 Ans:D 算出來是相等，不知道少考慮到甚麼因素?? 2.This morning Pat went to the market with a red bag and a greenn one. If he bought 10 carrots and 6 radishes, in how many ways could he distribute these vegetable so that no bag would be empty? Ans:75 3.In how many ways can the letters of the word POLLOLOP be arranged? Ans:560 4. Ten chair are evenly spaced around a round table and numbered clockwise from 1 to 10. Five married couple are to sit in the chairs with men and women alternating, and no one is to sit either next to or directly across from his or her spouse. How many seating arrangements are possible? Ans:560 我算出來是240..........>< 只能說我排列組合超爛= =" 5. what is the greatest integer n such that rs/n is an integer for all consecutive even integers r and s? Ans:8 6.when 2/9 of the vote on a certain resolution have been counted,3/4 of those counted are in favor of the resolution. what fraction of the remaining votes must be against the resolution so that the total count will result in a vote of 2 to 1 against the resolution? Ans:11/14 以上，麻煩大家了 多謝!! -- ※ 發信站: 批踢踢實業坊(ptt.cc) ◆ From: 143.215.98.9
推
06/08 06:09, , 1F
columnA= +1(or -1)columnB
06/08 06:09, 1F
推
06/08 07:17, , 2F
1.9次方就不一定是正的
06/08 07:17, 2F
推
06/08 07:21, , 3F
3. 8!/(2!*3!*3!) = 560
06/08 07:21, 3F
推
06/08 07:26, , 4F
5. RS/N N最大則rs/n儘可能最小 所以取2跟4=>n=8
06/08 07:26, 4F
推
06/08 07:31, , 5F
6. 設另一邊的7/9中 against的佔x favor佔1-x
06/08 07:31, 5F
→
06/08 07:33, , 6F
可以得到 (7x/9 + 2/9 * 1/4) = 2[7(1-x)/9 + 3/18]
06/08 07:33, 6F
→
06/08 07:34, , 7F
x算出來即為解
06/08 07:34, 7F
推
06/08 11:08, , 8F
2.G(0radish+carrots)+R(6radish+0~9carrots)=10ways
06/08 11:08, 8F
→
06/08 11:09, , 9F
G(6radishes+carrots)+R(0raish+1~10carrots)=10ways
06/08 11:09, 9F
→
06/08 11:10, , 10F
其他
06/08 11:10, 10F
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06/08 11:11, , 11F
G(1radish+carrots)+R(5raishes+0~11carrots)=11ways
06/08 11:11, 11F
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06/08 11:11, , 12F
G(2radish+carrots)+R(4raishes+0~11carrots)=11ways
06/08 11:11, 12F
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06/08 11:11, , 13F
G(3radish+carrots)+R(3raishes+0~11carrots)=11ways
06/08 11:11, 13F
→
06/08 11:11, , 14F
G(3radish+carrots)+R(3raishes+0~11carrots)=11ways
06/08 11:11, 14F
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06/08 11:12, , 15F
G(4radish+carrots)+R(2raishes+0~11carrots)=11ways
06/08 11:12, 15F
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06/08 11:12, , 16F
G(5radish+carrots)+R(1raishes+0~11carrots)=11ways
06/08 11:12, 16F
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06/08 11:13, , 17F
所以是10+11*5+10=75種; G(3rd...多貼ㄧ行,抱歉!
06/08 11:13, 17F
推
06/08 13:01, , 18F
我覺得第二題只要(6+1)*(10+1)-2(empty)就好了耶...
06/08 13:01, 18F
推
06/08 14:55, , 19F
樓上可以解釋一下前兩個()內的意思嗎?我參不太透
06/08 14:55, 19F
推
06/08 15:26, , 20F
4. 我算是480耶
06/08 15:26, 20F
→
06/08 15:27, , 21F
先取一人坐任意位置，有10種選擇
06/08 15:27, 21F
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06/08 15:29, , 22F
跟他同性的坐法有 4! = 24 種坐法
06/08 15:29, 22F
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06/08 15:30, , 23F
他的配偶只有 2 個位置可選且會決定其他異性的坐位
06/08 15:30, 23F
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06/08 15:31, , 24F
所以是 10*24*2 = 480
06/08 15:31, 24F
推
06/09 01:35, , 25F
H大 6+1是指radish每個袋子中可變化的數量0~6
06/09 01:35, 25F
→
06/09 01:36, , 26F
10+1則是carrot 的數量變化 0~10
06/09 01:36, 26F
→
06/09 01:36, , 27F
這樣會是所有的組合～扣掉兩種會有空袋子的情況
06/09 01:36, 27F
→
06/09 01:36, , 28F
答案就是75
06/09 01:36, 28F
推
06/09 02:11, , 29F
回coldstone大~他的配偶的位置也會影響其他人的配偶
06/09 02:11, 29F
推
06/09 02:25, , 30F
看到第四題四選一的機率比較大
06/09 02:25, 30F
推
06/09 02:34, , 31F
我認為各數要比480少耶~"~
06/09 02:34, 31F
推
06/09 09:25, , 32F
回sean2449大 因為配偶會影響其他配偶
06/09 09:25, 32F
→
06/09 09:26, , 33F
其中A的配偶A'只能選A的順時鐘或逆時鐘第四個位置
06/09 09:26, 33F
→
06/09 09:27, , 34F
當A'選了其中之一其他配偶的位置就固定了
06/09 09:27, 34F
→
06/09 09:28, , 35F
(一樣順時鐘或逆時鐘)
06/09 09:28, 35F
→
06/09 09:29, , 36F
所以配偶的部分我只乘二 因此至少有480坐法
06/09 09:29, 36F
推
06/10 16:46, , 37F
4. 480 +1
06/10 16:46, 37F
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文章代碼(AID): #1Dxfss6E (GRE)