Two electric dipoles of dipole moments $1.2\times {10}^{-30} \mathrm{cm}$ and $2.4\times {10}^{-30} \mathrm{cm}$ are placed in two difference uniform electric fields of strengths $5\times {10}^4 \mathrm{N} {\mathrm{C}}^{-1}$ and $15\times {10}^4 \mathrm{N} {\mathrm{C}}^{-1}$ respectively. The ratio of maximum torque experienced by the electric dipoles will be $\frac{1}{x}$. The value of $x$ is _____ .