Question

A is complement event of A. If P(A) - P(A) = 0.8 then find P(A).​
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Answer 1

Answer:

P(A)=0.5 and P(AB)=0.8

When A and B are independent events,

P(A∩B)=P(A)×P(B)

⇒P(A)+P(B)−P(A∪B)=0.5×q

⇒0.5+q−0.8=0.5q

⇒0.5q=0.3

⇒q=0.6

When A and B are mutually exclusive events

P(A∩B)=0

P(A)+P(B)=P(A∪B)

0.5+p=0.8

⇒p=0.3

Hence the ratio of q and p is 2