作者Linbookhow (寂寞黑絲襪)
看板GRE
標題[計量] 請教陳向東數學三題
時間Tue Sep 11 00:12:24 2012
此題為陳向東"最新GRE數學預測模擬試題(一)"，p257
16. Draw all diagonals in a regular eight-sided polygon. What is the
largest number of diagonals that meet in a single point?
(A) 2
(B) 3
(C) 4
(D) 5
(E) 6
這題的答案是(C)，除了用畫圖以外我想不太到有什麼好的方法可以解
下面二題為陳向東"最新GRE數學預測模擬試題(三)"，p265
24. The 20 people at party are divided into n mutually exclusive groups
in such a way that the number of people in any group does not exceed
the number in any other group by more than 1.
Quantity A Quantity B
The value of nif at least
one of the groups consists 6
of 3 people
這題的答案是D，但是我看不懂Quantity A中"the valure of nif"的意思。
25. In a group of 100 students, more students are on the fencing team
than are members of the French club. If 70 are in the club and 20
are ntither on the team nor in the club, what, is the minimum
number of students who could, be both on the team and in the club?
(A) 10
(B) 49
(C) 50
(D) 60
(E) 61
這題的答案是(E)，但我怎麼算都弄不出這個答案！
請好心的高手幫忙指點~~謝謝了！
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◆ From: 1.160.30.29
推 jerry771210 :第一題不是除以2? 09/11 00:44
推 george31708 :24應該是打錯了。我覺得是the value of n if ..... 09/11 02:18
→ george31708 :所以只有3,4或是3,2這兩種可能的人數 09/11 02:23
推 acegikmo :請問第一題是問 1.一個頂點可畫出幾條對角線 09/11 08:33
→ acegikmo :還是 2.所有對角線，最多可以有幾條交在同一點? 09/11 08:34
→ acegikmo :那如果假設是第二個問法，答案可以是5嗎 09/11 08:34
→ acegikmo :因為從一頂點畫出的五條對角線，確實也交在一點 09/11 08:35
→ acegikmo :就是他們共同的頂點阿~ 09/11 08:36
→ acegikmo :這樣的想法可以嗎? 09/11 08:37
推 george31708 :我的想法跟樓上也一樣。但是答案很奇怪 09/11 12:11
→ Linbookhow :我也認為是第2種問法，但是這樣的問法滿怪的 09/12 21:37