Hi,

I know the answer to this question but I am not sure how they worked it out. I know the method to work it out.

'

Steve, Katerina and Jess are three students who have agreed to take part in a psychology experiment. Each student is to answer several sets of multiple-choice questions. Each set has the same number of questions, n, where n is a number greater than 20. For each question there are four possible options (A, B, C or D), of which only one is correct.

If Katerina answers a question correctly, the probability that she will answer the next question correctly is 3/4 . If she answers a question incorrectly, the probability that she will answer the next question incorrectly is 2/3

.

In a particular set, Katerina answers Question 1 incorrectly.

b. i. Calculate the probability that Katerina will answer Questions 3, 4 and 5 correctly.

ii. Find the probability that Katerina will answer Question 25 correctly. Give your answer correct to

four decimal places.