Densities $(),$ Young's moduli $(E),$ and thermal conductivities $()$ of two different materials A and $B$ are given in the table below. Let $x$ denotes the material produced by mixing A and $B,$ and assume that the material properties of $x$ are the weighted mean of material properties of A and $B.$ For example, when $x$ is made of A and $B$ with mixture ratio of a and $b,{}_x=a{}_A+b{}_B$ where $a+b=1.$

$\backslash$table$[[,$Density,Young's modulus,Conductivity$],[A,{}_A,E_A,{}_A$