Since one of the offspring has white fur both of Sam's rabbits have a genotype of Gw. G standing for the dominate trait of grey fur while w stands for the recessive trait of white fur. When you put this information in a genotype chart you will get these possible genotypes for their offspring: GG, Gw, Gw, and ww. This means that there is a 75% chance that the offspring will have grey fur while there is a 25% chance they will have white fur. So this is how we know that Sam's rabbits most likely have genotypes of Gw.
