Question

Three liquids of densities $d,2d$ and $3d$ are mixed in equal volumes. Then the density of the mixture is

• A. $d$
• B. $2d$
• C. $3d$
• D. $5d$

Answer 1

The correct option is B $2d$

Density of mixture,
${\rho }_{\text{mixture}}=\frac{m_1+m_2+m_3}{V_1+V_2+V_3}$
Since $V_1=V_2=V_3=V$ (given)
$\therefore m_1=dV,m_2=2dV$ and $m_3=3dV$
$\Rightarrow {\rho }_{\text{mixture}}=\frac{dV+2dV+3dV}{3V}$
$=\frac{V(d+2d+3d)}{3V}$
$\Rightarrow {\rho }_{\text{mixture}}=2d$