Answer
The center of mass is located $6.46\times10^{-11}m$ away from the carbon atom.
Work Step by Step
Take the location of the carbon atom to be $0$; the location of the oxygen atom, therefore, will be $x_O=1.13\times10^{-10}m$
We also have $m_C=0.75m_O$
From the formula of the center of mass, $$x_{cm}=\frac{(m_C\times0)+m_Ox_O}{m_C+m_O}=\frac{m_Ox_O}{m_C+m_O}$$ $$x_{cm}=\frac{m_Ox_O}{0.75m_O+m_O}=\frac{x_O}{0.75+1}=\frac{x_O}{1.75}$$ $$x_{cm}=6.46\times10^{-11}m$$
So the center of mass is located $6.46\times10^{-11}m$ away from the carbon atom.
