Gmatprep question - sequence
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- jayhawk2001
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Interesting question. I'll post the OA after few folks reply.
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Is it B?
(1) Just knowing a1 doesn't help as k is unknown. If k is a big negative number, all terms might be less than 10, and if k is huge positive number, all may be greater than 10.
(2) If k is positive, a9 through a15 (7 terms) are greater than 10 and a1 through a7 (7 terms) are less than 10.
If k is negative, a9 through a15 are less than 10 and a1 through a7 are more than 10.
So in either case the answer is 7.
(1) Just knowing a1 doesn't help as k is unknown. If k is a big negative number, all terms might be less than 10, and if k is huge positive number, all may be greater than 10.
(2) If k is positive, a9 through a15 (7 terms) are greater than 10 and a1 through a7 (7 terms) are less than 10.
If k is negative, a9 through a15 are less than 10 and a1 through a7 are more than 10.
So in either case the answer is 7.
- gabriel
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good analysis ...rajesh_ctm wrote:Is it B?
(1) Just knowing a1 doesn't help as k is unknown. If k is a big negative number, all terms might be less than 10, and if k is huge positive number, all may be greater than 10.
(2) If k is positive, a9 through a15 (7 terms) are greater than 10 and a1 through a7 (7 terms) are less than 10.
If k is negative, a9 through a15 are less than 10 and a1 through a7 are more than 10.
So in either case the answer is 7.
me too getting the answer as B .. reason same as above ...
- jayhawk2001
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