Let's assume for this problem that the world is divided into blue-eyed people and brown-eyed people. Let's also assume for the sake of simplicity that there is only one gene responsible for eye color and that the allele for brown eyes (B) is dominant over the allele for blue eyes (b). Let's also assume that blue-eyed people and brown-eyed people randomly intermarry.

Calculate the probability of a Bb person and a blue-eyed person having a blue-eyed child. Construct a Punnet square for this.