Find the probability of the indicated event if p(e) =0.25 and p(f) =0.50

Question

Find P(e or f) if p( e and f) =0.20

Answer 1

P(e or f) = P(e) + P(f) - P(e and f)

P(e or f) = 0.25 + 0.50 - 0.20

P(e or f) = 0.55