UPSC NDA Math Model Paper 4

To find : The probability of neither A nor B i.e. find P(A∩B)
We Know that
P(A∩B)=1−P(A∪B) .......(1)
Given, The probability of happening of an event A is 0.5 and that of B is 0.3
A and B are mutually exclusive events.
⇒P(A∩B)=0
We know P(A∪B)=P(A)+P(B)−P(A∩B)
⇒P(A∪B)=0.3+0.5
⇒P(A∪B)=0.8
Equation (1) becomes
P(A∩B)=1−0.8=0.2