Human blood may contain either or both of two antigens, A and B. Blood that contains only the A antigen is called type A, blood that contains only the B antigen is called type B, blood that contains both antigens is called type AB, and blood that contains neither antigen is called type O. At a certain blood bank, 35% of the blood donors have type A blood, 10% have type B, and 5% have type AB.

Round the answers to two decimal places

(a) What is the probability that a randomly chosen blood donor is type O?

(b) A recipient with type A blood may safely receive blood from a donor whose blood does not contain the B antigen. What is the probability that a randomly chosen blood donor may donate to a recipient with type A blood?

(c) If someone has the A antigen, what is the probability that they are type AB?

A. Based on the initial statistics, 50% of the blood type is blood type O, hence the probability of choosing bold type O at random is 50/100, which is 0.50 to two decimal places.

B. The total number of donors that can donate to Blood type A is 85%, thus, the probability is 85/100, which is 0.85 to two decimal places.

C. The percentage of people that have the type AB blood is 5%, thus the probability of someone having the A antigen and blood type AB is 5/100, which is 0.05 to two decimal places.