The equation that relates the conductance G with the conductivity [tex]\sigma[/tex] is given by
[tex]G=\sigma \frac{A}{L} [/tex]
where A is the cross-sectional area while L is the length of the conduit.
In our problem, the area is [tex]A=0.40 cm^2=0.40 \cdot 10^{-4}m^2[/tex] and the length is [tex]L=20.0 cm=0.20 m[/tex], while the conductance G is [tex]G = 0.08 S[/tex], therefore re-arranging the equation we can find the conductivity:
[tex]\sigma = G \frac{L}{A}=0.08 S \frac{0.20 m}{0.40 \cdot 10^{-4}m^2}=400 S/m [/tex]
