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#1 2013-12-26 20:48:02
- niharika_kumar
- Member
- From: Numeraland
- Registered: 2013-02-12
- Posts: 1,062
sum of nos.
If N is the sum of first 13986 prime nos. , then N is always divisible by
options:-
a) 6
b) 4
c) 8
d) none of these
friendship is tan 90°.
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#2 2013-12-26 20:59:43
- bobbym
- bumpkin
- From: Bumpkinland
- Registered: 2009-04-12
- Posts: 109,606
Re: sum of nos.
Hi;
Choose d.
In mathematics, you don't understand things. You just get used to them.
If it ain't broke, fix it until it is.
Always satisfy the Prime Directive of getting the right answer above all else.
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#3 2013-12-27 00:47:23
- anonimnystefy
- Real Member
- From: Harlan's World
- Registered: 2011-05-23
- Posts: 16,049
Re: sum of nos.
I agree. That sum is never divisible by 2, so it cannot be divisible by any of those, either.
Here lies the reader who will never open this book. He is forever dead.
Taking a new step, uttering a new word, is what people fear most. ― Fyodor Dostoyevsky, Crime and Punishment
The knowledge of some things as a function of age is a delta function.
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#4 2013-12-27 02:43:08
- bobbym
- bumpkin
- From: Bumpkinland
- Registered: 2009-04-12
- Posts: 109,606
Re: sum of nos.
Depending on what number of them she picks to sum. First 2 equal 5. First 3, equal 10. First 4 equal 17.
The pattern repeats. If she picks an even number to sum the sum will be odd. If she picks an odd number to sum then the sum will be even. 13986 is even so the sum is odd.
In mathematics, you don't understand things. You just get used to them.
If it ain't broke, fix it until it is.
Always satisfy the Prime Directive of getting the right answer above all else.
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#5 2013-12-27 04:01:25
- niharika_kumar
- Member
- From: Numeraland
- Registered: 2013-02-12
- Posts: 1,062
Re: sum of nos.
hmm..
primes are interesting.
thank you 
friendship is tan 90°.
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#6 2013-12-27 04:21:47
- bobbym
- bumpkin
- From: Bumpkinland
- Registered: 2009-04-12
- Posts: 109,606
Re: sum of nos.
Hi;
Yep, number theory is very interesting.
In mathematics, you don't understand things. You just get used to them.
If it ain't broke, fix it until it is.
Always satisfy the Prime Directive of getting the right answer above all else.
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