A thermometer graduated according to a linear scale reads a value $x_0$ when in contact with boiling water, and $\mathrm{x}_0 /{ }^3$ when in contact with ice. What is the temperature of an object in ${ }^{\circ} \mathrm{C}$, if this thermometer in the contact with the object reads $\mathrm{x}_0 / 2$ ?