Arthur D. answered • 04/08/15
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8967 is the seventeenth term
8976
Arthur D.
tutor
Hi Helen,
I don't know of any formula for a problem like this. However, you can narrow the problem down by doing the following: there are 4 digits and therefore 4! numbers. 4*3*2*1=24 4-digit numbers. The numbers come in groups of 6 because there are 24 permutations and 4 digits; 24/4=6. Six numbers start with 6, six numbers start with 7, six with 8, and 6 with 9.Where is the seventeenth number ? (6, 12, 18, 24) The seventeenth number is in the third group of 6, the group that starts with 8. So you only have to write the permutations that start with 8, not the previous 12 permutations. Also the seventeenth term is the next to last greatest permutation in the group so you can work backwards and only have to write 2 permutations to get the answer.
Hope this is helpful.
Arthur D.
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04/10/15
Arthur D.
tutor
Helen, you're very welcome for the help. Not everyone says "thank you". A lot do but many don't.
Arthur D.
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04/10/15
Helen H.
Once again BIG thank you for further assistance. It all seems so easy the way you sorted it. XX Helen
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04/11/15
Arthur D.
tutor
Once again, you're very welcome. I'm glad I could help.
Arthur D.
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04/11/15
Helen H.
04/09/15