The A.P. Statistics exam consists of a multiple-choice section in which each question has five choices. Sara estimates that she
has a 75% chance of knowing each question. If she does not know the answer, she will randomly guess. a) What is the probability of Sara getting a question correct?
b) The A.P. exam has 40 questions, how many might Sara expect to get correct?
A) 75% she knows for sure Out of the remaining 25%, she has a 1/5 or 20% chance of getting it right. So, 1/4 x 1/5 x 100 = 5% Total chance of getting a question right: 75 + 5 = 80% b) If the total is 40, she can expect to get 80% x 40 = 32 questions correct.
