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![[Post New]](/templates/default/images/icon_minipost_new.gif) 22 Mar 2008 20:52:40 IST
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well solve another
the sum of the odd factors of 10! which are of the form 3m+1: m belongs to natural no.s
a 192
b 207
c 308
d none | |
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none..pl chk question once
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Nitwit Blubber Odment Tweak
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22 Mar 2008 20:58:42 IST
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the question is very correct ans is 207
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22 Mar 2008 21:09:57 IST
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10! = 2 8 . 34 . 52 .7
Now find the odd factors which are of the form 3m+1
Since the factors are odd, we don't have to consider the factors containing 2. and since it is of the form 3m+1, we dont have to consider factors containing 3.
Now only 52 and 7 are left. these form the factors 1, 5 , 7 , 25, 35 and 175 .
Only 7,25 and 175 are of the form 3m+1 .
( note that 1 = 3(0) +1 , but 0 is not a natural no.)
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22 Mar 2008 21:16:59 IST
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thanks
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