probability in math

Question

There are 34 employees in a certain firm. We know that of 24 these employees are​ male, 4 of these males are​ secretaries, and 9 secretaries are employed by the firm. What is the probability that an employee chosen at random is a​ secretary, given that the person is a ​female?

Answer 1

Use a tree diagram to solve problem.

9 secretaries total, and 4 are male, so 5 must be female

male (24) ----> secretary (4)

not secretary (20)

female (10) -----> secretary (5)

not secretary (5)

probability secretary given a female = 5/10 = 1/2