A laboratory technician is preparing a calibration standard by mixing two liquids. A volume V1 V_1\,V1 of Liquid 1 (density ρ1\rho_1ρ1) is mixed thoroughly with a mass m2 m_2\,m2 of Liquid 2 (density ρ2\rho_2ρ2) to form a single, uniform solution.

Assuming the total volume of the mixture is exactly equal to the sum of the individual volumes of the two liquids, which of the following is the correct expression for the density of the mixture, ρmix\rho_{\text{mix}}ρmix?