Question

Two substances of densities $\rho _ { l }$ and $\rho _ { 2 }$ are

• A. $\rho _ { 1 } = 6$and$\rho _ { 2 } = 2$
• B. $\rho _ { 1 } = 3$and$\rho _ { 2 } = 5$
• C. $\rho _ { 1 } = 12$and$\rho _ { 2 } = 4$
• D. None of these

Answer 1

Answer: (A)

$\rho _ { 1 } = 6$and$\rho _ { 2 } = 2$

Answer 2

When substances are mixed in equal volume then density

$\rho _ { 1 } + \rho _ { 2 } = 8$ .......(i)

When substances are mixed in equal masses then density

$2 \rho _ { 1 } \rho _ { 2 } = 3 \left( \rho _ { 1 } + \rho _ { 2 } \right)$ .......(ii)

By solving (i) and (ii) we get $\rho _ { 2 } = 2$.