Grace
2 cups black paint + 1 cup white paint
percent of white paint = (cups white paint / total cups of paint) × 100 = (1/3)×100 = 33.3%
Chase
7 cups black paint + 3 cups white paint
percent of white paint = (cups white paint / total cups of paint) × 100 = (3/10)×100 = 30%
Grace's gray is lighter since it has a greater percentage of white paint