A sequence a1,a2,a3....an of n integers is such that ak=k if k is odd and ak=-ak if k is even. Is the sum of the terms in the sequence positive?
1.) n is odd
2.) ak is positive
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ruchisharma
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Geva@EconomistGMAT
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Something is wrong: ak=-ak (when k is even) means that ak is equal to its negative self? I'm assuming the original question meant Ak=-k, or Ak=-a(k-1) (each term is equal to minus the previous term), but please check.
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Laura GMAT Tutor
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I think I've seen this question before so this might be what the OP meant.
Ruchisharma, if this your question?
A(sub k) = k if k= odd and A(sub k) = -k if k= even.
That would mean the sequence would go:
1, -2, 3, -4, 5, -6.
I think Ruchisharma mistyped the question as "ak=-ak" when it was really "ak=-k".
If this IS the real question, I'm still not sure how to help because statement (2) is confusing. From statement (2) do you mean that the final term in the sequence is positive?
Ruchisharma, if this your question?
A(sub k) = k if k= odd and A(sub k) = -k if k= even.
That would mean the sequence would go:
1, -2, 3, -4, 5, -6.
I think Ruchisharma mistyped the question as "ak=-ak" when it was really "ak=-k".
If this IS the real question, I'm still not sure how to help because statement (2) is confusing. From statement (2) do you mean that the final term in the sequence is positive?
