Problem $4.$ Working with Hydraulic Conductivity

In the figure below, the characteristics for three geological formations that overlie one another are shown. A constant$-$velocity vertical flow field exists across the three formations. The hydraulic head is $18$

b$)$ Calculate the specific discharge through the entire system? $(6$ points$)$

c$)$ Calculate the hydraulic head at points A and B in the figure $($note these are between the geological formations$)?(8$ points$)$