MGMAT CAT1

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MGMAT CAT1

by tanvis1120 » Tue Sep 16, 2014 4:21 pm
Hi Experts,

I eliminated the second statement due to the following reason:
The second-to-last term is 3^10. So, the last one should be 3^11.
But the catch is that, the target question does not provide any information about the elements of the sequence being -ve, +ve, integer of fraction. So, we fail to determine the very first term of the sequence. Consequently we cannot decide the fourth term as well. INSUFFICIENT

The reason provided by Manhattan:
(2) INSUFFICIENT: We can use this information to find the last term and previous terms, however, we don't know how many terms there are between the second-to-last term and the fourth term.

I have hard time grasping the concept, especially the underlined portion. Could you please tell me if there is anything wrong in my reasoning? Also, what exactly does manhattan reasoning mean?
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by [email protected] » Tue Sep 16, 2014 5:36 pm
Hi tanvis1120,

Your explanation and the one offered by Manhattan are essentially the same: you don't know the exact value of the fourth term because you don't know how the second-to-last term relates to the 4th term.

Using the information from the prompt and the information in Fact 2, we could have a variety of situations. For example:

5th term: 3^10
6th term: 3^11
4th term: 3^9

The answer to the question is 3^9

6th term: 3^10
7th term: 3^11
5th term: 3^9
4th term: 3^8

The answer to the question is 3^8

So Fact 2 is INSUFFICIENT

GMAT assassins aren't born, they're made,
Rich
Contact Rich at [email protected]
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by tanvis1120 » Tue Sep 16, 2014 6:23 pm
Okays.. Got it..
Thanks Rich!