American Red Cross. The American Red Cross must track their supply and demand for various blood types.

They estimate that about 45% of the U.S. population has Type O blood, 40% Type A, 11% Type B, and the rest Type AB.

a) If someone volunteers to give blood, what is the probability that this donor:

i) Has Type AB blood?

ii) Has Type A or Type B blood?

iii) Is not Type O?

b) Among four potential donors, what is the probability that:

i) All are Type O?

ii) None have Type AB blood?

iii) Not all are Type A?

iv) At least one person is Type B?