For a class activity, your group has been assigned the task of generating a quiz question that requires use of the formula for conditional probability to compute P(B | A). Your group comes up with the following question: “If P(A and B) = 0.40 and P(A) = 0.20, what is the value of P(B | A)?” What is wrong with this question? Hint: Consider the answer you get when using the correct formula, P(B | A) = P(A and B) /P(A) .