Question: Blood. Only 4% of people have Type AB blood.
a) On average, how many donors must be checked to find someone with Type AB blood?
b) What's the probability that there is a Type AB donor among the first 5 people checked?
c) What's the probability that the first Type AB donor will be found among the first 6 people?
d) What's the probability that we won't find a Type AB donor before the 10th person?