Source: Official Guide for GMAT Review 2016 Data Sufficiency ; #12

1

If sequence S has 120 terms, what is

If sequence S has 120 terms, what is the 105th term of S?

1 Explanation

1

John Robertson

Question: Sequence S has 120 terms, what is the 105th term of S

1) First term of S is -8
-> It starts at -8, but you don't know anything else than that, does it go by 2's, 10's, etc. S105 could be a number of values depending on this
INSUFF

2) Each term of S after the first term is 10 more than the term before
->You know the order/pacing of the sequence, but no idea where it starts. S105 could be a number of values depending on the starting point
INSUFF

1&2)
You know it starts at -8, and goes by 10's. S105 can be determined.
SUFF

Answer: C, both taken together are SUFF, neither alone are SUFF.

Dec 29, 2016 • Comment

Sam Kinsman, Magoosh Tutor

Yes, that's right John. Thanks for posting! :D

Dec 30, 2016 • Reply

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Official GMAT Material

Official Guide for GMAT Review 2016

Official Guide for the GMAT 2015 14th Ed.

Official Guide for the GMAT 13th Ed.

Official Guide for the GMAT 12th Ed.

Revised GRE PDF 2nd Ed.


Section 6.3 Data Sufficiency

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