$3-$ In the figure shown below,

a$.$ What is the flow rate through the soil sample, if the crosssectional area of the soil column is $10i{n}^2?$ Note that you need to convert some of the units.

Hint: One way to solve this problem is to replace the two soils with one soil, having an equivalent hydraulic conductivity.

b$.$ What is the vertical effective stress at points A$,$ B$,$ and C$,$ if the valve is closed?

c$.$ What is the vertical effective stress at points A$,$ B$,$ and C$,$ if the valve is open, and steady state conditions have been achieved? The given unit weights are saturated unit weights.