作者neopunk (Angelic whisper)
看板GRE_Verbal
标题[计量] 来欣Q1练习
时间Fri Oct 19 21:56:16 2007
24. If n is any prime number greater than 2, than
which of the following cannot be a prime number?
(a) n-4
(b) n-3
(c) n-1
(d) n+2
(e) n+5
答案给的是(e)
但我个人觉得应该是(c)
(prime必不是2的倍数，故此数减1就不可能又是质数)
大家的看法如何~~
先谢过 :D
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※ 发信站: 批踢踢实业坊(ptt.cc)
◆ From: 122.121.11.104
1F：推 mhcai:n=3时，(c)就破功啦 59.112.183.239 10/19 21:58
2F：推 neopunk:真的耶 囧 那这题只能用列举法来做罗? 122.121.11.104 10/19 22:04
3F：推 sawang:n+5不管怎麽样一订都不会是质数122.124.132.226 10/20 00:35
4F：推 smallmilk:n=3时,n-1=2, 2是质数.... 218.168.132.71 10/20 17:02