Bunuel wrote:
If sequence S has 100 terms, what is the 83rd term of S?
(1) The first term of S is 23
(2) Each term after the first term of S is 5 less than the preceding term
Target question: What is the 83rd term of S? Statement 1: The first term of S is 23 We have no idea how this sequence progresses. So, there's no way to determine the 83rd term.
Since we can answer the
target question with certainty, statement 1 is SUFFICIENT
Statement 2: Each term after the first term of S is 5 less than the preceding termOkay, so we know HOW the sequence progresses, but we don't know the specific value of any term.
Since we cannot answer the
target question with certainty, statement 2 is NOT SUFFICIENT
Statements 1 and 2 combined Term 1 = 23 (from statement 1)
Term 2 = 23 - 5 = 18 (from statement 2)
Term 3 = 18 - 5 = 13
And so on....
Since we COULD keep this pattern going indefinitely, we COULD easily find the value of the 83rd term.
Of course, we're not going to waste any time determining the actual value of the 83rd term. All we need to do is determine whether the combined statements are sufficient to answer the target question. Since we COULD answer the
target question with certainty, the combined statements are SUFFICIENT
Answer =
Cheers,
Brent
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