
A market share puzzle
In a certain market there exists two brands of cereal from two competing companies. Brand X and Y. It is known from historical data
 The probability that a customer using brand X would hop to brand Y in a given year is 12%
 The probability that a customer using brand Y would hop to brand X in a given year is 10%
After spending some money on advertising brand X is known to have 30% market share. What would the market share of X be after 3 years?
Answer: Probability Puzzles: A Cereal Market Share Puzzle