Will 3 regulation size women's basketballs fit in a standard rim at the same time?

No, three regulation size women's basketballs will not fit in a standard Basketball rim at the same time. A regulation women's basketball has a circumference of about 29.5 inches, while a standard rim has a diameter of 18 inches. Since the combined width of the three basketballs exceeds the rim's diameter, they cannot all fit simultaneously.