Margie (of mass 50 kg) and Bill (of mass 65 kg), both with brand new roller blades, are at rest facing each other in the parking lot.

Margie (of mass 50 kg) and Bill (of mass65 kg), both with brand new roller blades,are at rest facing each other in the parkinglot. They push off each other and move inopposite directions, with Margie moving at aconstant speed of 16 ft/s .At what speed is Bill moving?Answer in units of ft/s.