The task I am struggling with: Mt. Kinley is a strategy consulting firm that divides its consultants into three classes: associates, managers, and partners. The firm has been stable in size for the...

The task I am struggling with:

Mt. Kinley is a strategy consulting firm that divides its consultants into three classes: associates, managers, and partners. The firm has been stable in size for the last 20 years, ignoring growth opportunities in the 90s, but also not suffering from a need to downsize in the recession at the beginning of the 21st century. Specifically, there have been – and are expected to be – 200 associates, 60 managers, and 20 partners. The work environment at Mr. Kinley is rather competitive. After four years of working as an associate, a consultant goes “either up or out”; that is, becomes a manager or is dismissed from the company. Similarly, after six years a manager either becomes a partner or is dismissed. The company recruits MBA’s as associate consultants; no hires are made at the manager or partner level. A partner stays with the company for another 10 years (a total of 20 years with the company).
a) How many new MBA graduates does Mt. Kinley have to hire every year?
b) What are the odds that an new hire at Mr. Kinley will become partner (as opposed to being dismissed after 4 years of 10 years)?

Thank you very much for your help.