A Recent Survey Shows That the Probability of a College

Multiple Choice

A recent survey shows that the probability of a college student drinking alcohol is 0.6. Further, given that the student is over 21 years old, the probability of drinking alcohol is 0.8. It is also known that 30% of the college students are over 21 years old. The probability of drinking or being over 21 years old is ________.

A) 0.24.
B) 0.42.
C) 0.66.
D) 0.90.