F.6 續概率 easy~ (check&ask)

4.
P(不同水果)=P(A芒B橙 ORA橙B芒 )=1/4x1/3+3/4x2/3=7/12
5.
(a) P=1/2x1/2=1/4
(b) P=4/52x36/52=9/169
6
(b) P=P(only I pass OR only II pass)=2/5x3/8+3/5x5/8=21/40
7
(b) P=0.04x(1-0.03)=0.0388
8
(a) P=0.4x0.6x0.6=0.144
(b)P=0.6x0.6x0.6=0.216


2012-05-17 10:13:40 補充：
9
(a) P=P(both are 1-5)=5/6x5/6=25/36
(b) P=P(3,6 OR 4,5)X2=(1/36+1/36)x2=1/9
(c) P(1st>2nd)+P(1st=2nd)+P(1st<2nd)=1
P(1st>2nd)x2+1/6=1
P(1st>2nd)=5/12

4) 1/4 x 1/3 + 3/4 x 2/3