Question

Report probabilities to three decimal places (but don’t round until you have your final answer). Show your work.

1. Twenty people donate blood at a blood drive: 9 type A, 2 type B, 1 type AB, and 8 type O.
a) If two donations are selected at random with replacement, what is the probability that exactly one is type O?
b) If two donations are selected at random with replacement, what is the probability that at least one is type O?
c) If two donations are selected at random without replacement, what is the probability that at least one is type O?

d) If three donations are selected at random without replacement, what is the probability that at least one is type O?

Answer 1