Given S={E1,E2,E3,E4,E5,E6,E7,E8,E9}
A={E1,E5,E8},B={E2,E5,E8,E9}
P(E1)=P(E2)=0.08
P(E3)=P(E4)=P(E5)=0.1
P(E6)=P(E7)=2,P(E8)=P(E9)=0.07
(i) P(A)=P(E1)+P(E5)+P(E8)
=0.08+0.1+0.07=0.25
(ii) P(A∪B)=P(A)+P(B)-P(A∩B)
Now, P(B)=P(E2)+P(E5)+P(E8)+P(E9)
=0.08+0.1+0.07+0.07=0.32
A∩B={E5,E8}
P(A∩B)=P(E5)+P(E8)=0.1+0.7=0.17
On substituting these values in Eq. (i), we get
P(A∪B)=0.25+0.32-0.17=0.40
(iii) A∪B={E1,E2,E5,E8,E9}
P(A∪B)=P(E1)+P(E2)+P(E5)+P(E8)+P(E9)
=0.08+0.08+0.1+0.07+0.07=0.40
(iv) ∵P
-
(B)
=1-P(B)=1-0.32=0.68
and
-
B
={E1,E3,E4,E6,E7}
(iv) ∵ P
-
(B)
=P(E1)+P(E3)+P(E4)+P(E6)+P(E7)
=0.08+0.1+0.1+0.2+0.2=0.68