Purple flowers (P) are dominant over white flowers (p). Round seeds (R) are dominant over wrinkled seeds (r). Green seeds (G) are dominant over yellow seeds (g). You cross a plant that is heterozygous...

Purple flowers (P) are dominant over white flowers (p). Round seeds (R) are dominant over wrinkled seeds (r). Green seeds (G) are dominant over yellow seeds (g). You cross a plant that is heterozygous for Purple flowers, heterozygous for Round seeds and homozygous for yellow seeds with a plant that is homozygous for white flowers, heterozygous for Round seeds and heterozygous for Green seeds.

What is the probability the offspring from this cross will express at least 2 dominant traits?  Express your answer as a reduced fraction.