Answer:
Number of baseball cards miles has=24
Miles wants to display cards in even number of rows.
⇒Array=ab, where a is number of rows and b is number of columns.
So, possible number of arrays are
1.→24× 1 or 1 × 24
2.→2× 12 or 12 × 2
3.→3×8 or 8 × 3
4.→4×6 or 6 × 4
Arrays in which rows are even
1.→24 × 1
2.→8×3
3.→12×2
4.→6×4
5.→2×12
6.→12×2
Arrays in which columns are even
→1 × 24
→3×8
→4×6
→6×4
→2×12
→12×2
Arrays in which both rows and columns are even
→4×6
→6×4
→12×2
→2×12