Question 354931
Probability that she approves qualified = 0.80*0.80 = 0.64
probability that she doesn't approve qualified = 0.80*0.20 = 0.16
probability that she approves unqualified = 0.80*0.20 = 0.16
probability that she doesn't approve unqualified = 0.20*0.20 = 0.04
Then by the formula for conditional probability,
P(unqualified|not approved) = P(unqualified and not approved)/P(not approved)
= 0.04/(0.16+0.04) = 0.04/0.20 = 0.20.