Can anyone help with a center of mass question?

Question

A molecule consists of two atoms. The atoms have masses of 15 u and 13 u and are 1.70 10-10 m apart. How far from the first atom is the center of mass of the molecule?

Answer 1

[13 u/ (15u + 13u)] * 1.7 10^-10 m

= 8 x10^-11 m