Answer
${x_{cm}} \approx 1.1\,m$
Work Step by Step
We know that
${X_{c.o.m.}} = \frac{{{m_1}{x_1} + {m_2}{x_2} + {m_3}{x_3}}}{{{m_1} + {m_2} + {m_3}}}$
We also know that
${m_1} = 3kg$
${m_2} = 4kg$
${m_3} = 8kg$
${x_1} = 0$
${x_2} = 2\,m$
${x_3} = 1\,m$
Substituting these values in the formula and solving:
${x_{cm}} = \frac{{0 + \left( {4 \times 2} \right) + \left( {8 \times 1} \right)}}{{3 + 4 + 8}} = 1.067$
${x_{cm}} \approx 1.1\,m$
