HMMT 二月 2000 · POW 赛 · 第 3 题

英文原题

3. Assume that a hand of thirteen ards is dealt from a randomized de k of 52 ards. Let
   A be the probabilit y that the hand on tains t w o a es. Let B be the probabilit y that it on tains t w o a es if y ou already kno w it on tains at least one a e. Let C be theprobabilit y that it on tains at least t w o a es if y ou already kno w it on tains an a e ofhearts. W rite do wn the inequalit y relationship b et w een A , B and C , i.e. one p ossibilit yis A = B > C .