$[10]3.$ For steady$-$state seepage shown in the Figure to the right, water levels are maintained at the levels shown and water flows through the soil $($shown in gray$)$ from B to $A.$ The cross$-$sectional area of the soil sample perpendicular to flow is $2500m{m}^2$ and soil permeability $k$ is $5m\frac{m}{s}.$

$($a$)$ What is the pressure head at point A$?$

$($b$)$ What is the hydraulic gradient $i$ in the sample from point B to A$?$

$($c$)$ Determine the volume of water which discharges in $10$ min.

$($d$)$ Suppose the location of the upstream overflow is changed and the head loss between the upstream and downstream overflows becomes $500$ mm $.$ How much water would discharge in $10$ min $?$