Probability based on contingency table.
Form the summarized table, please answer the following problems:

Skill

Experience

Book Keeping

Reception

Word Processing

Total

Less than one year

15

5

30

50

One to three years

5

10

5

20

More than three years

5

15

10

30

Total

25

30

45

100

One person's file is selected at random. Find out the probability that the selected person would fall into the following categories.
a) Book keeping
b) Less than one year of experience
c) Reception
d) One to three years of experience
e) Word Processing
f) More than three years of experience