Awoman with blue eyes (bb) and a man with brown eyes (bb) has a child. what is the percentage change that the child will have blue eyes?

The percentage chance that the child will have blue eyes is: 25%.

Explanation:

According to Mendel laws, there would be a 50% chance of having a child that is heterozygous for the gene (Bb) but happens to express brown eyes because this is the dominant allele;  there's 25% chance of having a child who  is homozygous for the dominant allele (BB) and will also have brown eyes; finally, there's a 25% chance of having a child who is homozygous for the recessive allele (bb) so their phenotype will be blue eyes.