How far from the center of the earth is the center of mass of the earth + moon system?

The mass of the Moon is 7.35*1022 kg and the mass of the Earth is 6.00*1024 kg. The distance between the Moon and the Earth is 3.80*105 km. Since the radius of the Earth is 6378 km, the center of mass of the Earth-Moon system is inside the Earth.

A. to determine if humans can explore mars safely

Answer body lying face up ;