Please help... I am using the conditional probability formula but not getting correct answer.

Formulas I am using are below:

P(A and B) = P(A) * P(B)

P(A and B) = P(A) * P(B|A)

P(A and B) = P(B) * P(A|B)

Given P(A) = 0.5 and P(B) = 0.4, do the following. (For each answer, enter a number.) (a) If A and B are mutually exclusive events, compute P(A or B). (b) If P(A and B) = 0.3, compute P(A or B). Need Help? Read ItGiven P(A) = 0.2 and P(B) = 0.8, do the following. (For each answer, enter a number.) (a) If A and B are independent events, compute P(A and B). 0.16 (b) If P(A | B) = 0.3, compute P(A and B). 0.25 Need Help? Read It