Charges $\mathrm{Q}$, $2\mathrm{Q}$ and $-\mathrm{Q}$ are given to three concentric conducting spherical shells $\mathrm{A}$, $\mathrm{B}$ and $\mathrm{C}$ respectively, as shown in the figure. The ratio of charges on the inner and outer surfaces of the shell $\mathrm{C}$ will be