If the 1st term of a sequence is 0 and the 2nd term is 1...

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If the 1st term of a sequence is 0 and the 2nd term is 1, is the 5th term 2 ?

(1) Each odd-numbered term is either 0 or 2.
(2) The 3rd term is 2.

E

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by Ian Stewart » Sun Apr 28, 2019 12:05 am

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Statement 1 tells us that the fifth term is either 0 or 2. There's no other information anywhere in the question that tells us anything about the fifth term in the sequence, so using both statements, we have two possibilities, and the answer is E.
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by Brent@GMATPrepNow » Sun Apr 28, 2019 6:40 am

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AbeNeedsAnswers wrote:If the 1st term of a sequence is 0 and the 2nd term is 1, is the 5th term 2 ?

(1) Each odd-numbered term is either 0 or 2.
(2) The 3rd term is 2.
E
Given: term1 = 0 and term2 = 1

Target question: Does term5 equal 2?
Once we scan the two statements, we can probably jump straight to
.
.
.
Statements 1 and 2 combined
There are several possible sequences that satisfy BOTH statements. Here are two:
Case a: {0, 1, 2, 0, 2,...}. In this case, the answer to the target question is YES, term5 IS 2
Case b: {0, 1, 2, 0, 0,...}. In this case, the answer to the target question is NO, term5 is NOT 2
Since we cannot answer the target question with certainty, the combined statements are NOT SUFFICIENT

Answer: E

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by [email protected] » Sun Apr 28, 2019 11:34 am

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Hi All,

We're told that the 1st term of a sequence is 0 and the 2nd term is 1. We're asked if the 5th term in the sequence is 2. To properly answer any sequence question, we need to know the underlying pattern or formula behind it.

(1) Each odd-numbered term is either 0 or 2.

Fact 1 limits the possible values for the 5th term - it can only be 0 or 2. However, we don't know which one it is, so the answer to the question could be NO (if the 5th term is 0) or YES (if the 5th term is 2).
Fact 1 is INSUFFICIENT

(2) The 3rd term is 2.

Fact 2 gives us another term to work with (so we know that the sequence begins with 0, 1, 2...), but this tells us nothing about how the sequence "works", so we cannot deduce the values of any other terms in the sequence.
Fact 2 is INSUFFICIENT

Combined, we know...
Each odd-numbered term is either 0 or 2.
The 3rd term is 2.

Even combined, we still don't know what the 5th term is; with two possible values (and 2 different corresponding answers), the answer could be YES OR NO.
Combined, INSUFFICIENT

Final Answer: E

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