give a try

來源: passenger101 於 2009-01-08 07:13:22 [] [博客] [舊帖] [給我悄悄話] 閱讀數 : (303 bytes)
回答: 每周一道奧賽題 (6) 由 本來清靜 於 2009-01-07 13:32:40

I'm not sure if I unstand correctly.

If p/q 小數點後麵第2的n次方位 (x)is 2, 4, 5, 7, 8, then 2/9, 4/9, 5/9, 7/9, 8/9 must give solution. If x is 0, 3/10^(n+1), must give solution. If x is 1, 3, then 13/100, 31/100, will give solution. If x is 6, then 2/3 give the solution. If x=9, then 9/10^n,

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