Question

The prob(A|B)) is the same as?

a. prob(B|A)

b. prob(A U B)

c. prob(A*B)

d. none of the abov

Answer 1

P(A|B) = P(A ∩ B) / P(B).

None of the given options are equal in general:
- P(B|A) = P(A ∩ B) / P(A) (not the same except in special cases, e.g. P(A)=P(B)),
- P(A ∪ B) is P(A)+P(B)−P(A ∩ B),
- P(A * B) presumably means P(A ∩ B), which is missing the division by P(B).

So answer: d. none of the above.