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DS w/ variable and prime #

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mwilliams82
 Post subject: DS w/ variable and prime #
 Post Posted: Sun Aug 30, 2009 2:41 pm 
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Students


Posts: 8
If M and N are positive integers and mn=k, M+N=K+1?

1. m=1

2. k is a prime number

The OA for this problem is D but statement two eludes me. Can anyone explain how 2 is sufficient?

Thanks
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itheenigma
 Post subject: Re: DS w/ variable and prime #
 Post Posted: Sun Aug 30, 2009 4:28 pm 
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Students


Posts: 2
mwilliams82 wrote:
If M and N are positive integers and mn=k, M+N=K+1?

1. m=1

2. k is a prime number

The OA for this problem is D but statement two eludes me. Can anyone explain how 2 is sufficient?

Thanks


The answer seems right.
The problem states that k has 2 factors in 'm' and 'n'.
Now, according to statement 2, if k is a prime number, then either 'm' or 'n' has to be equal to 'k' and consequently, the other must be equal to 1 (prime number property).

In either case, M+N will be equal to K+1
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mwilliams82
 Post subject: Re: DS w/ variable and prime #
 Post Posted: Sun Aug 30, 2009 10:55 pm 
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Students


Posts: 8
Yep. Thought it was something obvious that I was overlooking.

Thanks.
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RonPurewal
 Post subject: Re: DS w/ variable and prime #
 Post Posted: Fri Sep 25, 2009 11:15 pm 
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ManhattanGMAT Staff


Posts: 7146
itheenigma wrote:
mwilliams82 wrote:
If M and N are positive integers and mn=k, M+N=K+1?

1. m=1

2. k is a prime number

The OA for this problem is D but statement two eludes me. Can anyone explain how 2 is sufficient?

Thanks


The answer seems right.
The problem states that k has 2 factors in 'm' and 'n'.
Now, according to statement 2, if k is a prime number, then either 'm' or 'n' has to be equal to 'k' and consequently, the other must be equal to 1 (prime number property).

In either case, M+N will be equal to K+1


nicely done.
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