Genetics problem?

Question

Genetics problem?
I'm usually opposed to ppl who post their homework on here, but I'm stuck on this problem:

A father of a certain family belongs to blood group AB, and the mother belongs to blood group O. They have four children, one belonging AB, one to group A, one to group B, and one to O. One of these children is adopted and another child is from an earlier marriage of the mother. State whih is the adopted child and which is the child from an earlier marriage.

Answer 1

Since the father is Type AB, he has alleles A and B.
Since mother is Type O, he has alleles O and O.

Children:
Type AB This child is adopted because there is no O from the mother at all.
Type A
Type B
Type O This child is from an earlier marriage because there is an O from Mom and and O from Dad (who isn't the current father).

Answer 2

Father :: AB X OO :: Mother

All their biological children have to be EITHER AO or BO. An O allele from the mother must be present, and an A or a B from the father too. That leaves the other two...

Any children of the mother has to have the O allele, so the child from an earlier marriage is O (and his father, the mother's previous husband, had to be OO too).
That leaves out the child with AB, that CAN NOT be this mother's son, so is the adopted one.

Answer 3

you do not say if this is intercourse-appropriate, so we''ll anticipate this is easy Mendelian genetics, then it may be D for dominant, greater digits. And d for the classic # of digits. Dad could desire to be Dd or DD. mom is dd. babies could desire to be Dd : dd, 2/4 greater, 2/4 primary, for the 1st circulate. babies could be all Dd, 4/4 greater for the 2d circulate. however the daughter is primary, dd. So, Dad is Dd. So this is the 1st one, Dd:Dd, the place there's a 50/50 probability.