According to Wien's displacement law, the wavelength corresponding to maximum spectral emissive power is inversely proportional to the absolute temperature of the emitting body ($\lambda_{\text{max}} \propto \frac{1}{T}$). The order of wavelengths for the given colours in the visible spectrum is $\lambda_{\text{violet}} < \lambda_{\text{green}} < \lambda_{\text{red}}$. Given that stars $P$, $R$, and $Q$ have maximum intensity at violet, green, and red colours respectively, we have $\lambda_P < \lambda_R < \lambda_Q$. Since temperature is inversely proportional to the wavelength of maximum intensity, the temperatures of the stars will follow the reverse order: $T_P > T_R > T_Q$.