Difference between revisions of "2010 AMC 10B Problems/Problem 23"

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==Notes==
 
==Notes==
There is a general formula (coming from the fields of [[combinatorics]] and [[representation theory]]) to answer problems of this form; it is known as the [http://en.wikipedia.org/wiki/Young_tableau#Dimension_of_a_representation hook-length formula]. This formula gives the answer of <math>42</math>.
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There is a general formula (coming from the fields of [[combinatorics]] and [[representation theory]]) to answer problems of this form; it is known as the [http://en.wikipedia.org/wiki/Young_tableau#Dimension_of_a_representation hook-length formula]. This formula gives the answer of <math>42 </math>.
  
 
== See also ==
 
== See also ==
 
{{AMC10 box|year=2010|ab=B|num-b=22|num-a=24}}
 
{{AMC10 box|year=2010|ab=B|num-b=22|num-a=24}}
 
{{MAA Notice}}
 
{{MAA Notice}}

Revision as of 16:55, 4 August 2014

Problem

The entries in a $3 \times 3$ array include all the digits from 1 through 9, arranged so that the entries in every row and column are in increasing order. How many such arrays are there?

$\textbf{(A)}\ 18\qquad\textbf{(B)}\ 24 \qquad\textbf{(C)}\ 36\qquad\textbf{(D)}\ 42\qquad\textbf{(E)}\ 60$

Notes

There is a general formula (coming from the fields of combinatorics and representation theory) to answer problems of this form; it is known as the hook-length formula. This formula gives the answer of $42$.

See also

2010 AMC 10B (ProblemsAnswer KeyResources)
Preceded by
Problem 22
Followed by
Problem 24
1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25
All AMC 10 Problems and Solutions

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