ycd927 发表于 2011-4-4 21:24:40

初二竞赛题

1．有面值为10元、20元、50元的人民币（每种至少一张），合计1000元，那么面值为20元的人民币有（
）张
2.由1，2，3这三个数字组成四位数，在每个四位数中，这三个数字至少出现一次．这样的四位数有（



）个
3．已知一个有序数组http://preview.mail.126.com/proxy.do?keyfrom=wm126&sid=VApcRebshFSHjHrjzOssDqHCksqIKesN&mid=194%3A1tbiwh0X30X9dtefZQAAs0&part=3&filename=%E7%AC%AC19%E5%B1%8A%E2%80%9C%E5%B8%8C%E6%9C%9B%E6%9D%AF%E2%80%9D%E5%85%A8%E5%9B%BD%E6%95%B0%E5%AD%A6%E9%82%80%E8%AF%B7%E8%B5%9B%E5%88%9D%E4%BA%8C%E7%AC%AC2%E8%AF%95%E8%AF%95%E9%A2%98.doc%2F%E7%AC%AC19%E5%B1%8A%E2%80%9C%E5%B8%8C%E6%9C%9B%E6%9D%AF%E2%80%9D%E5%85%A8%E5%9B%BD%E6%95%B0%E5%AD%A6%E9%82%80%E8%AF%B7%E8%B5%9B%E5%88%9D%E4%BA%8C%E7%AC%AC2%E8%AF%95%E8%AF%95%E9%A2%98.files%2Ffile0102.gif，现按下列方式重新写成数组http://preview.mail.126.com/proxy.do?keyfrom=wm126&sid=VApcRebshFSHjHrjzOssDqHCksqIKesN&mid=194%3A1tbiwh0X30X9dtefZQAAs0&part=3&filename=%E7%AC%AC19%E5%B1%8A%E2%80%9C%E5%B8%8C%E6%9C%9B%E6%9D%AF%E2%80%9D%E5%85%A8%E5%9B%BD%E6%95%B0%E5%AD%A6%E9%82%80%E8%AF%B7%E8%B5%9B%E5%88%9D%E4%BA%8C%E7%AC%AC2%E8%AF%95%E8%AF%95%E9%A2%98.doc%2F%E7%AC%AC19%E5%B1%8A%E2%80%9C%E5%B8%8C%E6%9C%9B%E6%9D%AF%E2%80%9D%E5%85%A8%E5%9B%BD%E6%95%B0%E5%AD%A6%E9%82%80%E8%AF%B7%E8%B5%9B%E5%88%9D%E4%BA%8C%E7%AC%AC2%E8%AF%95%E8%AF%95%E9%A2%98.files%2Ffile0104.gif，使
http://preview.mail.126.com/proxy.do?keyfrom=wm126&sid=VApcRebshFSHjHrjzOssDqHCksqIKesN&mid=194%3A1tbiwh0X30X9dtefZQAAs0&part=3&filename=%E7%AC%AC19%E5%B1%8A%E2%80%9C%E5%B8%8C%E6%9C%9B%E6%9D%AF%E2%80%9D%E5%85%A8%E5%9B%BD%E6%95%B0%E5%AD%A6%E9%82%80%E8%AF%B7%E8%B5%9B%E5%88%9D%E4%BA%8C%E7%AC%AC2%E8%AF%95%E8%AF%95%E9%A2%98.doc%2F%E7%AC%AC19%E5%B1%8A%E2%80%9C%E5%B8%8C%E6%9C%9B%E6%9D%AF%E2%80%9D%E5%85%A8%E5%9B%BD%E6%95%B0%E5%AD%A6%E9%82%80%E8%AF%B7%E8%B5%9B%E5%88%9D%E4%BA%8C%E7%AC%AC2%E8%AF%95%E8%AF%95%E9%A2%98.files%2Ffile0106.gif，
http://preview.mail.126.com/proxy.do?keyfrom=wm126&sid=VApcRebshFSHjHrjzOssDqHCksqIKesN&mid=194%3A1tbiwh0X30X9dtefZQAAs0&part=3&filename=%E7%AC%AC19%E5%B1%8A%E2%80%9C%E5%B8%8C%E6%9C%9B%E6%9D%AF%E2%80%9D%E5%85%A8%E5%9B%BD%E6%95%B0%E5%AD%A6%E9%82%80%E8%AF%B7%E8%B5%9B%E5%88%9D%E4%BA%8C%E7%AC%AC2%E8%AF%95%E8%AF%95%E9%A2%98.doc%2F%E7%AC%AC19%E5%B1%8A%E2%80%9C%E5%B8%8C%E6%9C%9B%E6%9D%AF%E2%80%9D%E5%85%A8%E5%9B%BD%E6%95%B0%E5%AD%A6%E9%82%80%E8%AF%B7%E8%B5%9B%E5%88%9D%E4%BA%8C%E7%AC%AC2%E8%AF%95%E8%AF%95%E9%A2%98.files%2Ffile0108.gif按照这个规律继续写出http://preview.mail.126.com/proxy.do?keyfrom=wm126&sid=VApcRebshFSHjHrjzOssDqHCksqIKesN&mid=194%3A1tbiwh0X30X9dtefZQAAs0&part=3&filename=%E7%AC%AC19%E5%B1%8A%E2%80%9C%E5%B8%8C%E6%9C%9B%E6%9D%AF%E2%80%9D%E5%85%A8%E5%9B%BD%E6%95%B0%E5%AD%A6%E9%82%80%E8%AF%B7%E8%B5%9B%E5%88%9D%E4%BA%8C%E7%AC%AC2%E8%AF%95%E8%AF%95%E9%A2%98.doc%2F%E7%AC%AC19%E5%B1%8A%E2%80%9C%E5%B8%8C%E6%9C%9B%E6%9D%AF%E2%80%9D%E5%85%A8%E5%9B%BD%E6%95%B0%E5%AD%A6%E9%82%80%E8%AF%B7%E8%B5%9B%E5%88%9D%E4%BA%8C%E7%AC%AC2%E8%AF%95%E8%AF%95%E9%A2%98.files%2Ffile0109.gif，…，http://preview.mail.126.com/proxy.do?keyfrom=wm126&sid=VApcRebshFSHjHrjzOssDqHCksqIKesN&mid=194%3A1tbiwh0X30X9dtefZQAAs0&part=3&filename=%E7%AC%AC19%E5%B1%8A%E2%80%9C%E5%B8%8C%E6%9C%9B%E6%9D%AF%E2%80%9D%E5%85%A8%E5%9B%BD%E6%95%B0%E5%AD%A6%E9%82%80%E8%AF%B7%E8%B5%9B%E5%88%9D%E4%BA%8C%E7%AC%AC2%E8%AF%95%E8%AF%95%E9%A2%98.doc%2F%E7%AC%AC19%E5%B1%8A%E2%80%9C%E5%B8%8C%E6%9C%9B%E6%9D%AF%E2%80%9D%E5%85%A8%E5%9B%BD%E6%95%B0%E5%AD%A6%E9%82%80%E8%AF%B7%E8%B5%9B%E5%88%9D%E4%BA%8C%E7%AC%AC2%E8%AF%95%E8%AF%95%E9%A2%98.files%2Ffile0111.gif，若http://preview.mail.126.com/proxy.do?keyfrom=wm126&sid=VApcRebshFSHjHrjzOssDqHCksqIKesN&mid=194%3A1tbiwh0X30X9dtefZQAAs0&part=3&filename=%E7%AC%AC19%E5%B1%8A%E2%80%9C%E5%B8%8C%E6%9C%9B%E6%9D%AF%E2%80%9D%E5%85%A8%E5%9B%BD%E6%95%B0%E5%AD%A6%E9%82%80%E8%AF%B7%E8%B5%9B%E5%88%9D%E4%BA%8C%E7%AC%AC2%E8%AF%95%E8%AF%95%E9%A2%98.doc%2F%E7%AC%AC19%E5%B1%8A%E2%80%9C%E5%B8%8C%E6%9C%9B%E6%9D%AF%E2%80%9D%E5%85%A8%E5%9B%BD%E6%95%B0%E5%AD%A6%E9%82%80%E8%AF%B7%E8%B5%9B%E5%88%9D%E4%BA%8C%E7%AC%AC2%E8%AF%95%E8%AF%95%E9%A2%98.files%2Ffile0113.gif，则http://preview.mail.126.com/proxy.do?keyfrom=wm126&sid=VApcRebshFSHjHrjzOssDqHCksqIKesN&mid=194%3A1tbiwh0X30X9dtefZQAAs0&part=3&filename=%E7%AC%AC19%E5%B1%8A%E2%80%9C%E5%B8%8C%E6%9C%9B%E6%9D%AF%E2%80%9D%E5%85%A8%E5%9B%BD%E6%95%B0%E5%AD%A6%E9%82%80%E8%AF%B7%E8%B5%9B%E5%88%9D%E4%BA%8C%E7%AC%AC2%E8%AF%95%E8%AF%95%E9%A2%98.doc%2F%E7%AC%AC19%E5%B1%8A%E2%80%9C%E5%B8%8C%E6%9C%9B%E6%9D%AF%E2%80%9D%E5%85%A8%E5%9B%BD%E6%95%B0%E5%AD%A6%E9%82%80%E8%AF%B7%E8%B5%9B%E5%88%9D%E4%BA%8C%E7%AC%AC2%E8%AF%95%E8%AF%95%E9%A2%98.files%2Ffile0115.gif
．




我只知道答案，求过程。谢谢！

录 发表于 2011-4-4 21:31:21

希望杯的..二試

石崇的BOSS 发表于 2011-4-5 10:59:38

3题全是叉叉图片，楼主再修改一下吧

淡淡幽情KK 发表于 2011-4-5 12:10:24

1.1-47均可
2.A(2 3)*3=18

hjt0619 发表于 2011-4-6 00:53:59

回复 4# 的帖子

第二问 我算的是 C(4 2)*A(3 3)=36
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