Probability, basic principles
This problems is from 400 level probability class but introductory course. Please specify the terms you use (if necessary) and explain each step of your solutions. Thank you very much.
18. 45% of the students at U of M do neither have a tattoo nor a body piercing (other than an ear piercing). 40% of the students at U of M have a tattoo. 30% of the students at U of M have a body piercing. One student is randomly selected, what is the probability that this student has
a. a tattoo or a body piercing?
b. a tattoo and a body piercing?
c. only a tattoo or only a body piercing?