Answer:
2520.54463 km
Explanation:
The location of the center of mass is given by
[tex]r_{cm}=\frac{\sum m_j\vecr}{\sum m_j}[/tex]
Using Coordinates with the origin at the center of Pluto and the +x direction toward Charon, so
[tex]x_p[/tex] = 0
[tex]x_c[/tex] = 19700 km
[tex]m=\frac{4}{3}\pi r^3=\frac{1}{6}\pi d^3[/tex] = Mass
[tex]d_c[/tex] = Diameter of Charon
[tex]d_p[/tex] = Diameter of Pluto
[tex]\\\Rightarrow x_{cm}=\frac{m_px_p+m_cx_c}{m_p+m_c}\\\Rightarrow x_{cm}=\frac{m_c}{m_p+m_c}x_c=\frac{\frac{1}{6}\rho \pi d_c^3}{\frac{1}{6}\rho \pi d_p^3+\frac{1}{6}\rho \pi d_c^3}\\\Rightarrow x_{cm}=\frac{d_c^3}{d_p^3+d_c^3}x_c\\\Rightarrow x_{cm}=\frac{1250^3}{2370^3+1250^3}19700\\\Rightarrow x_{cm}=2520.54463\ km[/tex]
The location of the center of mass of this systemrelative to the center of Pluto is 2520.54463 km