2004 AMC 12A Problem 16

Attempt Problem 16 of the 2004 AMC 12A below, then check your answer against the professionally curated solution from LIVE by Po-Shen Loh. You can also try the full timed exam, view all 2004 AMC 12A solutions, or check the answer key.

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16.

The set of all real numbers xx for which log2004(log2003(log2002(log2001x)))\small \log_{2004}(\log_{2003}(\log_{2002}(\log_{2001} x))) is defined is {xx>c}.\{x \mid x \gt c\}. What is the value of c?c?

00

200120022001^{2002}

200220032002^{2003}

200320042003^{2004}

2001200220032001^{2002^{2003}}

Answer: B
Concepts:logarithminequality
Difficulty rating: 1660
Solution:

The expression is defined if and only if log2003(log2002(log2001x))>0,\log_{2003}(\log_{2002}(\log_{2001} x)) \gt 0, that is, log2002(log2001x)>1.\log_{2002}(\log_{2001} x) \gt 1.

This holds if and only if log2001x>2002,\log_{2001} x \gt 2002, which is equivalent to x>20012002.x \gt 2001^{2002}.

Therefore c=20012002.c = 2001^{2002}.

Thus, the correct answer is B.

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