People with O-negative blood are universal donors. That is, any patient can receive a transfusion of O-negative blood. If three people randomly arrive to donate blood at a blood drive, what is the probability that at least one of them is a universal donor?

Probability of at least 1 out of 3 being O-negative = 20.1%

Note: The question is incomplete. A similar question is given below:

People with type O-negative blood are universal donors. That is, any patient can receive a transfusion of O-negative blood. Only 7.2% of the American population have O-negative blood. If we choose 10 Americans at random who gave blood, what is the probability that at least 1 of them is a universal donor?

Step-by-step explanation:

Probability of O-negative blood in the population = 7.2% or 0.072

Probability of not being O-negative = 1 - P(O-negative) = 1 - 0.072 = 0.928

Using the multiplication rule to determine the probability of 10 people not being O-negative

Probability of 10 not negative = (P(not O-negative)¹⁰ = (0.928)¹⁰ = 0.4737

Hence, probability of at least 1 being O-negative = 1 - P(not O-negative) = 1 - 0.4737 = 0.5263

In percentage, P(at least 1 out of ten being O-negative) = 52.63%

Given 3 random donors

Probability of 3 not negative = (P(not O-negative)³ = (0.928)³ = 0.7991

Hence, probability of at least 1 being O-negative = 1 - P(3 not O-negative) = 1 - 0.7991 = 0.2009

In percentage, P(at least 1 out of 3 being O-negative) = 20.1%