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2010 AMC 10B Question 23

AMC10 · 2010 AMC 10B

Question 23

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?
  1. $18$
  2. $24$
  3. $36$
  4. $42$
  5. $60$