If the probability for A fail in an examination is 0.2 and that for B is 0.3, then the probability that either A or B fails is?

∵ P(A) = 0.2
∴ P(A) = 1 - 0.0 = 0.8
And P (B) = 0.3
∴ P(B) = 1 - 0.3 = 0.7
Required probability
= P(A ∪ B)
= P(A ∩ B)
= 1 - P (A ∩ B ) = 1 - P(A) P(B)
= 1 - (0.8) (0.7) = 1-0.56 = 0.44