2007 AMC 10B Problem 20


A set of 2525 square blocks is arranged into a 5×55 \times 5 square. How many different combinations of 33 blocks can be selected from that set so that no two are in the same row or column?

(A) 100(B) 125(C) 600(D) 2300(E) 3600\textbf{(A) } 100 \qquad\textbf{(B) } 125 \qquad\textbf{(C) } 600 \qquad\textbf{(D) } 2300 \qquad\textbf{(E) } 3600


Full credit goes to MAA for authoring these problems. These problems were taken on the AOPS website.

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Problem Tags: Counting and probability

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Category: AMC 10B
Points: 3
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