In a group of 40 people, 10 are healthy and every person the of the remaining 30 has either high blood pressure, a high level of cholesterol or both. If 15 have high blood pressure and 25 have high level of cholesterol,

a) how many people have high blood pressure and a high level of cholesterol?

If a person is selected randomly from this group, what is the probability that he/she

b) has high blood pressure (event A)?

c) has high level of cholesterol(event B)?