Current Attempt in Progress

Estimate $($a$)$ the maximum, and $($b$)$ the minimum thermal conductivity values $($in $\frac{W}{m}-K)$ for a cermet that contains $76$ vol$\%$ carbide particles in a metal matrix. Assume thermal conductivities of $21$ and $69\frac{W}{m}-$K for the carbide and metal, respectively.

$($a$)$ W$/$m$-$K

$($b$)$ W$/$m$-$K