Question

Three liquids of densities $d , 2 d$ and $3 d$ are mixed in equal proportions of weights. The relative density of the mixture is

• A. $\frac { 11 d } { 7 }$
• B. $\frac { 18 d } { 11 }$
• C. $\frac { 13 d } { 9 }$
• D. $\frac { 23 d } { 18 }$

Answer 1

Answer: (B)

$\frac { 18 d } { 11 }$

Answer 2

$\frac { 3 m } { V _ { 1 } + V _ { 2 } + V _ { 3 } } = \frac { 3 m } { \frac { m } { d } + \frac { m } { 2 d } + \frac { m } { 3 d } }$= $\frac { 3 \times 6 } { 11 } d = \frac { 18 } { 11 } d$