Official Guide Explanation:
Data Sufficiency #111




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Solution and Metadata

Question: 111
Page: 161
Difficulty: 5 (Moderate)
Category 1: Algebra > Functions > Sequences

Explanation: Given the rule for this sequence, if we know the first two terms, we can determine all of the successive terms. The same principle applies later in the sequence: If we know two consecutive terms, we can figure out all the later terms.

Statement (1) is sufficient. Since the 6th term is the sum of the 4th and 5th, if the 6th minus the 4th is 5, then the 5th term is 5. That's all we know, but that's what the question is asking for!

Statement (2) is insufficient. The sum of the 6th and 7th terms is the 8th term, so we know the value of the 8th term, but we don't know anything else. Choice (A) is correct.

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