Question

Two liquids having densities $d_{1}$ and $d_{2}$ are mixed in such a way that both have same mass. The density of the mixture is

• A. $\frac{d_{1}+d_{2}}{2}$
• B. $\frac{d_{1}+d_{2}}{d_{1} d_{2}}$
• C. $\frac{d_{1} d_{2}}{d_{1}+d_{2}}$
• D. $\frac{2 d_{1} d_{2}}{d_{1}+d_{2}}$

Answer 1

Answer: (D)

Let each have mass $=M$ and densities $d_{1}$ and $d_{2}$
$d_{mix}=\frac{M_{mix}}{V_{mix}}=\frac{M+M}{\left(\frac{M}{d_{1}}\right)+\left(\frac{M}{d_{2}}\right)}$
$=\frac{2 d_{1} d_{2}}{d_{1}+d_{2}}$