HMMT 二月 2009 · GEN2 赛 · 第 2 题
HMMT February 2009 — GEN2 Round — Problem 2
题目详情
英文原题
- [ 2 ] How many ways can you tile the white squares of following 2 × 24 grid with dominoes? (A dominocovers two adjacent squares, and a tiling is a non-overlapping arrangement of dominoes that coversevery white square and does not intersect any black square.)
2009
解析
英文解析
- [ 2 ] How many ways can you tile the white squares of following 2 × 24 grid with dominoes? (A dominocovers two adjacent squares, and a tiling is a non-overlapping arrangement of dominoes that coversevery white square and does not intersect any black square.)
Answer: 27
Solution: Divide the rectangle into three 3 × 8 sub-rectangles. It is easy to count that there are 3
ways of tiling each of these sub-rectangles independently, for a total of 3 = 27 possibilities.3
2009