If the depth of water table between two points $25$km and $30$km east of the point of discharge

changes by $0\mathrm{.}85$m$,$ and the permeability coefficient of the aquifer material is determined to be

$0\mathrm{.}864($m$)/($d$).$ If the pollutant disperses at a wide angle of approximately $60\backslash$deg from source, with an

adsorption rate coefficient, k$\_($a$)=(0\mathrm{.}55)/()$ day onto the aquifer media, determine the concentration at

a point $60$km from source