4. The personnel department of a company has records which show the followinganalysis of its 200 accountants. Age
Under 30
30 to 40
Over 40
Bachelor's degree only
90
20
40
Master's degree
10
30
10
If one accountant is selected at random from the company, find
a) The probability he has only a bachelor's degree.
b) The probability he has a master's degree, given that he is over 40.
c) The probability he is under 30, given that he has a bachelor's degree.