Q22 of 249 Page 31

Mark the correct alternative in each of the following:

If P (A ∪ B) = 0.8 and P (A ∩ B) = 0.3, then


For events A and B, addition theorem of probability →


P(A⋃B) = P(A) + P(B) – P(A⋂B) → (1)


Also,


→ (2)


→ (3)


Using equation (1)


0.8 = P(A) + P(B) – 0.3


P(A) + P(B) = 1.1


1 – P() + 1 – P() = 1.1 → From (2) & (3)


2 – {P() + P()} = 1.1


P() + P() = 2 – 1.1


P() + P() = 0.9

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