Two brown-eyed parents have produced three blue-eyed sons. if they have another child, how likely is it that the child will be brown-eyed

%

Explanation:

Two brown-eyed parents have produced three blue-eyed sons . This means that the parents have heterogyzous genotype with one blue allele. Here, brown color is dominant over the blue color of the eye.

Let, the brown color eye allele be represented by "B" and the blue color allele be represented by allele "b"

So the genotype of parents would be "Bb"

If a cross is carried out between two parents with genotype "Bb" the following offspring will be produced  -

Bb x Bb

BB, Bb, Bb, bb

So out of the four offspring three children have brown color eye.

Thus the probability of a child having brown color eye is

%