Well,
We need to make a Punnett square. Assuming that the man has type A, not AO or AA blood, we will have a 1 x 2 Punnett square. We just have to take the A on the left and pair it with either the A on the left column or the B on the right column.
Therefore, the percent chance of having an AA genotype is 1 in 2 or 50%, while the percent chance of having an AB genotype is 1 in 2 or 50%. Thus, the possible phenotypes are 50% A type blood and 50% AB type blood.
I have attached the resulting Punnett square.
