2010 AMC 10B Problems/Problem 23
Problem
The entries in a 
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?
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 
.
See also
| 2010 AMC 10B (Problems • Answer Key • Resources) | ||
| Preceded by Problem 22 |
Followed by Problem 24 | |
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| All AMC 10 Problems and Solutions | ||
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