Question

Equal masses of two substance having densities s1 and s2 are mixed together what is the density of the mixture

Answer 1

For liq 1, Density = s1 and Mass = m 
For liq 2, Density = s2 and Mass = m 
Vol of liq 1 = m/s1 
Vol of liq 2 = m/s2 
Total volume = m/s1 + m/s2 
= m(s1+s2) / s1s2 
Total mass = m+m= 2m 
Density of the mixture = Total Mass/ Total Volume 
=2m s1s2 / m(s1+s2) 
= s1s2/(s1+s2)