Maths Olympiad Prep

Library / /377 of 413

, 2008

Combinatorics Difficulty 3.0 AMC 10/12 Find the answer Canada

A 3×33 \times 3 grid is filled with the digits 1,21, 2 and 33 so that each number appears once in each row and column. Two different examples are (123312231)\begin{pmatrix}1&2&3\\3&1&2\\2&3&1\end{pmatrix} and (321213132)\begin{pmatrix}3&2&1\\2&1&3\\1&3&2\end{pmatrix}. How many different ways are there of filling the grid?

(A) 1414 (B) 1212 (C) 1010 (D) 88 (E) 66

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