Skip to content / Đến nội dung
ThichHocToan.com

2010 AMC 12B Question 17

AMC12 · 2010 AMC 12B

Question 17

The entries in a $3\times3$ 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. $60$