Tommy the Dunker's performance on the basketball court is influenced by his state of mind: If he scores, he is twice as likely to score on the next shot as he is to miss, whereas if he misses a shot, he is six times as likely to miss the next shot as he is to score. Required:
a. If Tommy has missed a shot, what is the probability that he will score two shots later?
b. In the long term, what percentage of shots are successful?