Puzzleup 2011 (01) Students - 拼圖

題目網址: www.puzzleup.com/2011/puzzle/?219
加分時限: 7/28(四) 7PM - 8/02(二) 7PM
答對可得基本分１００分。答案可上傳５次，每改１次答案從基本分扣２０分。
比賽期間內可隨時上傳答案，加分時限內答對第ｎ天加（６－ｎ）分　 　
另依題目的難易有額外加分（如有８０％的人這題答錯，答對者加８０分） 　　

◆Students

Each of the students in a group, writes down his or her name, surname,
age and birthplace on a card he or she holds. Then, these cards (each
containing four entries) are collected and examined. The following
observations are made:

‧ No matter which four cards are picked, at least two of them contains
an identical entry.
‧ There are at most three people in the group having the same name. (ie.
There may be 3 people named A, 3 people named B but there cannot be 4 people
named C).
‧ There are at most three people in the group having the same surname.
‧ There are at most three people in the group having the same age.
‧ There are at most three people in the group having the same birthplace.

What is the possible maximum number of students in this group?

每個學生手上有一張卡片，上面寫著各自的名字、姓氏、年齡、出生地４個項目，
收集並檢視所有卡片後得知:

‧任選４張卡片，至少兩張卡片上有一個項目完全相同。
‧這群學生裏最多有３人有相同的名字。（意即可以有3人叫A, 3人叫B, 但不能有
4人叫C。)
‧這群學生裏最多有３人有相同的姓氏。
‧這群學生裏最多有３人有相同的年齡。
‧這群學生裏最多有３人有相同的出生地。

問這群學生最多有幾人？

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不知道這題有沒有我想的那麼簡單
至於02題，英文看嘸...
哪位高手給翻一下please




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