\frac{m + ρ_{v} (1 - α) V}{V} = ρ_{v} \Rightarrow \frac{m}{V} = α ρ_{v} (*)

${\frac{m + \rho_v(1 - \alpha)V}{V} = \rho_v \quad\Rightarrow\quad \frac{m}{V} = \alpha \rho_v\quad\quad (\ast)}$

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