先后抛掷两枚骰子,出现的点数共有: (1,1),(1,2),(1,3),(1,4),(1,5),(1,6), (2,1),(2,2),(2,3),(2,4),(2,5),(2,6), (3,1),(3,2),(3,3),(3,4),(3,5),(3,6), (4,1),(4,2),(4,3),(4,4),(4,5),(4,6), (5,1),(5,2),(5,3),(5,4),(5,5),(5,6), (6,1),(6,2),(6,3),(6,4),(6,5),(6,6),共36种 其中点数之和是6的有5种,故P(A)=
点数之和是7的有6种,P(B)=
点数之和是8的有5种,故P(C)=
∴P(A)=P(C)<P(B). 故选A. |