Rh-positive blood appears in 85% of the white population in the United States. If 8 people are

Question:

Rh-positive blood appears in 85% of the white population in the United States. If 8 people are sampled at random from that population, find the probability that:
(a) At least 6 of them have Rh-positive blood.
(b) At most 3 of them have Rh-negative blood, that is, an absence of Rh positive.