0张A的概率为:C 4 50 / C 4 54
1张A的概率为:C 1 4 × C 3 50 / C 4 54
2张A的概率为:C 2 4 × C 2 50 / C 4 54
3张A的概率为:C 3 4 × C 1 50 / C 4 54
4张A的概率为:C 4 4 / C 4 54
0张A:50/54×49/53×48/52×47/51=0.728
1张A:4/54×50/53×49/52×48/51=0.062
2张A:4/54×3/53×50/52×49/51=0.00387
3张A:4/54×3/53×2/52×50/51=0.000158
4张A:4/54×3/53×2/52×1/51=0.00000316
4张A的概率:(4/54*(3/53)*(2/52)*(1/51)