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Topic: 2-digit Parade (Read 446 times) |
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Sir Col
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impudens simia et macrologus profundus fabulae
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2-digit Parade
« on: Nov 28th, 2008, 11:01am » |
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By selecting a single digit from the 5-digit number, 12345, it is possible to obtain five 1-digit numbers: 1, 2, 3, 4, and 5.
By selecting two digits from the same 5-digit number, 12345, it is possible to form twenty 2-digit numbers: 12, 13, 14, 15, 21, 23, 24, 25, 31, 32, 34, 35, 41, 42, 43, 45, 51, 52, 53, and 54.
a) Find the smallest positive integer that contains every 1-digit number.
b) Find the smallest positive integer that can be used to form every 2-digit number (10 to 99).
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| « Last Edit: Nov 28th, 2008, 2:36pm by Sir Col » |
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0.999...
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Re: 2-digit Parade
« Reply #1 on: Nov 28th, 2008, 1:45pm » |
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a) lim n-> 123456789/10n
b) lim n->112233445566778899/10n
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Sir Col
Uberpuzzler
impudens simia et macrologus profundus fabulae
Gender:
Posts: 1825
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Re: 2-digit Parade
« Reply #2 on: Nov 28th, 2008, 2:36pm » |
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Sorry, I should have said, "Find the smallest positive integer...". I've edited the problem wording.
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