The American Red Cross says that about 45% of the U.S. population has Type O blood, 40% Type A, 11% Type B, and the rest Type AB.
a). Someone volunteers to give blood. What is their probabitlity that this donor:
1. has Type AB blood?
2. has Type A or Type B blood?
3. Is NOT type O?
b). Among four potential donors, what is the probability that:
1. all are Type O?
2. no one is Type AB?
3. they are NOT all Type A?
4. at least one person is Type B?