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tanyajoseph
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 Posted: Mon Aug 13, 2007 12:56 pm Post subject: Sequence of nos |
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Can someone kindly explain this?
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bingojohn
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| Posted: Mon Aug 13, 2007 1:17 pm Post subject: Re: Sequence of nos |
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| tanyajoseph wrote: | | Can someone kindly explain this? |
looks like the following values would fit the sequence... going upto a ( 8 )
a(0) = 0
a(1) = 1
a(2) = -1
a(3) = 3
a(4) = -3
a(5) = 5
a(6) = -5
a(7) = 7
a ( 8 ) = -7
Statement (1): If n is odd, terms upto n-1 (n-1 is even) would cancel each other out and the sum would be positive
Statement (1) is sufficient
Statement (2): For a(n) to be positive, n has to be odd. The previous argument then applies. Sufficient.
Answer [D], each alone.
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ricaototti
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| Posted: Wed Sep 03, 2008 7:14 am Post subject: |
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but what if A1 = minus 3 .... Then, answer would have to be C no?
Why do u assume A1 to be positive if it is not told anywhere?
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schumi_gmat
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| Posted: Wed Sep 03, 2008 9:52 am Post subject: |
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a1 can never be -3. it is not an assumption
as it is said a(k) = k, a(1) = 1
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canuckclint
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| Posted: Wed Sep 03, 2008 9:59 am Post subject: |
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>but what if A1 = minus 3 .... Then, answer would have to be C no?
No.
a1 != -3 by definition
ak = k, if k is odd
so a1 = 1 and 1 only!
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kv_ajay
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| Posted: Wed Sep 03, 2008 10:54 am Post subject: |
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| can u tell me source of this practise test..people post lot many questions from these tests.
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sumithshah
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| Posted: Tue Sep 09, 2008 5:25 am Post subject: |
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| Its from a source called Power Prep - found in MBA.com
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