Blood type probability help with question

The Q uses the word "blood type" [very odd] - it is known as blood group!

The ABO blood group system is inherited in a co-dominant fashion, in which A and B alleles -are dominant over O allele.

So if you draw your usual punnet square for AO and BO, you end up with the below ratios in the F1 (children)

AO - 1: group A
BO - 1: group B
AB - 1: group AB
OO - 1: group O

The given group of O for the first child has no bearing on the outcome of the group of the second child (trick Q??)

The probability of the 2nd (or any) child being NOT OO genotype [therefore not O blood group] is the probability of him/her being AO [group A] OR AB [group AB] OR BO {group B]. As all four possibilities are of equal chance, the probability of the 2nd child [AND of any subsequent child, respectively] being NOT O group is 3 out of 4 = 75%.

Is that better? Good, well done!

M