Answer:
Probability of female P(f) = 0,575 or 57,5 %
Probability of physic majors P = 0,425 or 42,5 %
Step-by-step explanation:
a) Probability that a random selected student is female:
Let call P(f) such probability is P(f1) + P(f2)
we have to evaluate 2 branch of the tree, working as follows
1.Probability of students as physics major is P(f1)
17/40 and after that the probability of student physics majors being female is 7/17, Therefore for that side we have probability
P(f1) = ( 17/40)* (7/17) = 119/680
2.-Probability of students as female from 40 student is
16/40
Then P(f) = ( 119/680) + 16/40 P(f) = 391/680
P(f) = 0,575 or 57,5%
b) Probability of physics majosr is:
P(pm) = 17/40
P(pm) = 0,425 or 42,5 %
