Difference between revisions of "2003 AIME I Problems/Problem 1"

(Added problem and solution)
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Given that
 
Given that
  
<math> \frac{((3!)!)!}{3!} = k \cdot n!, </math>
+
<center><math> \frac{((3!)!)!}{3!} = k \cdot n!, </math></center>
  
 
where <math> k </math> and <math> n </math> are positive integers and <math> n </math> is as large as possible, find <math> k + n. </math>
 
where <math> k </math> and <math> n </math> are positive integers and <math> n </math> is as large as possible, find <math> k + n. </math>
  
 
== Solution ==
 
== Solution ==
<math> \frac{((3!)!)!}{3!} = \frac{(6!)!}{3!} = \frac{720!}{3!} = \frac{720!}{6} = \frac{720 \cdot 719!}{6} = 120 \cdot 719! = k \cdot n! </math>
+
We use the definition of a [[factorial]] to get
 +
 
 +
<center><math> \frac{((3!)!)!}{3!} = \frac{(6!)!}{3!} = \frac{720!}{3!} = \frac{720!}{6} = \frac{720 \cdot 719!}{6} = 120 \cdot 719! = k \cdot n! </math></center>
  
 
Therefore: <math> k + n = 120 + 719 = 839 </math>
 
Therefore: <math> k + n = 120 + 719 = 839 </math>

Revision as of 22:09, 15 July 2006

Problem

Given that

$\frac{((3!)!)!}{3!} = k \cdot n!,$

where $k$ and $n$ are positive integers and $n$ is as large as possible, find $k + n.$

Solution

We use the definition of a factorial to get

$\frac{((3!)!)!}{3!} = \frac{(6!)!}{3!} = \frac{720!}{3!} = \frac{720!}{6} = \frac{720 \cdot 719!}{6} = 120 \cdot 719! = k \cdot n!$

Therefore: $k + n = 120 + 719 = 839$

See also