2004 AMC 12A Problem 16

Below is the professionally curated solution for Problem 16 of the 2004 AMC 12A, 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.

All of the real AMC 8, AMC 10, AMC 12, and AIME problems in our complete solution collection are used with official legal permission of the Mathematical Association of America (MAA).

Concepts:logarithminequality

Difficulty rating: 1660

16.

The set of all real numbers xx for which log2004(log2003(log2002(log2001x)))\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}}

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.

Problem 16 in Other Years