✔ 最佳答案
a)P(The two cards are of the same unit)= P(Any 1st drawn card) * P(Any one of 3 other the same unit with the 1st card.)= (52/52) (3/51)= 3/51Alternatively :(13C1) (4C2) / 52C2= 3/51
b)P(The two cards are of different suits.)= P(Any 1st drawn card) * P(Any one of 13*3=39 other different suits cards.)= (52/52) * (39/51)= 39/51Alternatively :P(The two cards are of different suits.)= 1 - P(two cards with the same suit.)= 1 - (52/52)(12/51)= 39/51
c)P(at least one face card.)= 1 - P(two non-face cards)= 1 - (52 - 3*4) / 52](52 - 3*4 - 1) / 51= 1 - (40/52)(39/51)
= 1 - (10/13)(13/17)= 21/51
2011-02-03 23:29:57 補充:
a)
Answer 3/51 = 1/17
b)
Answer 39/51 = 13/17
c)
Answer 21/51 = 7/17