Question 762026
P(E or F) = P(E) + P(F) - P(E and F)


0.50 = 0.45 + P(F) - 0.20


0.50 = 0.25 + P(F)


0.50 - 0.25 = P(F)


0.25 = P(F)


P(F) = 0.25