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标题: 抢答题：你知道为什么吗 [打印本页]

作者: 新用户 时间: 2005-2-3 15:38
标题: 抢答题：你知道为什么吗

有一本82页的书，中间缺了一张，张涛将残书的页码相加，得到3314。老实说他算错了。你知道为什么吗。

限时：60秒 ~ 120秒

回帖请给出解释。

作者: ob 时间: 2005-2-3 20:01
标题: 回复：抢答题：你知道为什么吗

To add the page number from 1 to 82, get 3043. 3403-3314=89=44+45. Unless the book's first page has page numbers 1 and 2, otherwise, 张涛's calculation is correct.

作者: QL 时间: 2005-2-3 20:35
标题: 回复：回复：抢答题：你知道为什么吗

Since there are 82 pages, so the largest PAGE NUMBER should be 82*2 = 164.

Anyway, on each page, there are two consecutive page numbers, hence the sum of

them should be an odd number. Since there are even number of pages, the sum

of all the page numbers should be even.

Zhange said the sum of the remaining page numbers is odd, hence the sum of the

two missing page numbers is also odd. Impossible.

(we assume there are page numbers on both side of each page, we do

not consider the flyer, index pages etc)

作者: QL 时间: 2005-2-3 20:38
标题: 回复：回复：回复：抢答题：你知道为什么吗

I mean, EVEN number is impossible.

作者: 新用户 时间: 2005-2-3 21:36
标题: 回复：回复：回复：抢答题：你知道为什么吗

sorry, 怪我没有说清楚，我说82页，意思是41 pages, 82个数.

If 82 pages, 164 numbers, then yes, we could use your method, which is much simpler.

作者: QL 时间: 2005-2-3 21:43
标题: 回复：回复：回复：回复：抢答题：你知道为什么吗

then, follow ob's calculation, 44,45 are on two papers, but only one paper is missing.

作者: 新用户 时间: 2005-2-3 22:04
标题: Agree with you!

Agree with you!

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