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)?
d) has high blood pressure and high level of cholesterol (event A and B)?
e) has either high blood pressure or high level of cholesterol (event A or B)?
f) Use the above to check the probability formula: P(A or B) = P(A) + P(B) - P(A and B).