A housekeeper buys three kinds of cereal: A, B, C. She never buys the same cereal in successive weeks. If she buys cereal A, then the next week she buys cereal B. However, if she buys either B or C, then the next week she is three times as likely to buy A as the other brand.(b) In the long run, how often does she buy each of the three brands?

(a) Find the transition matrix.

How do I go about a matrix without numbers?