The probability that at least one of the events E1 and E2 occurs is 0.6 If the probability of the simultaneous occurrence of E1 and E2 is 0.2, find P(¯E1)+P(¯E2).
Given, P(E1∪E2)=0.6 and P(E1∩E2)=0.2.
∴P(E1∪E2)=P(E1)+P(E2)−P(E1∩E2)
⇒P(E1)+P(E2)=P(E1∪E2)+P(E1∩E2)=(0.6+0.2)=0.8
⇒P(E1)+P(E2)=0.8
⇒{1−P(¯E1)}+{1−P(¯E2)}=0.8
⇒P(¯E1)+P(¯E2)=(2−0.8)=1.2
Hence, P(¯E1)+P(¯E2)=1.2.