Question

Me 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?
a.) 0%
b.) 25%
c.) 50%
d.) 100%

Answer 1

The answer should be C, 50%

First we need to find the alleles for Mr Jones. We know that he has a blood type B, so at least one allele should be B, and the other can either be B or O (cannot be A, or else his blood type would be AB because A and B are co-dominant alleles)
Since Mr Jones' parents are both blood type AB, so which means their allels must be A and B, so, we can conclude that Mr Jones alleles should be B and B.

Now we know Mr jones' alleles, we can conduct a punnett square to find the probability. Since Mrs Jones has blood type AB, again, her alleles are also A and B.

From the punnett square attached, we can conclude that their offspring are either blood type AB or pure B. So, the answer should be 50%, C.