It is given that P(A)=0.3 and P(B)=0.4
(i) If A and B are independent events, then
P(A∩B)=P(A)⋅P(B)=0.3×0.4=0.12
(ii) It is known that, P(A∪B)=P(A)+P(B)−P(A∩B)
⇒P(A∪B)=0.3+0.4−0.12=0.58
(iii) It is known that, P(A|B)=P(A∩B)P(B)
⇒P(A|B)=0.120.4=0.3
(iv) It is known that, P(B|A)=P(A∩B)P(A)
⇒P(B|A)=0.120.3=0.4