Many programming teams work independently at a large software company. The management has been putting pressure on these teams to finish a project on time. The company currently has 18 large programming projects, of which only 12 are likely to finish on time. Suppose the manager decides to randomly supervise three such projects.
a. What is the probability that all three are likely to finish on time?
b. What is the probability that at least two are likely to finish on time?