Question

Mr. Jones has blood type B and Mrs. Jones has blood type AB. What is the probability that they will have a child with blood type A if both of Mr. Jones’s parents were AB?

Answer 1

If both of Mr Jone's parents were AB, then the possible blood types of their children would be AA, AB, and BB. This means that Mr Jones has a pure type B blood. Using the Punnett square to determine the possible blood type of their children
| B | B
A | AB | AB
B | BB | BB

The possible blood types of their children are AB and BB. So there is 0 probability that they will have a child of blood type A.