Consider the profile in problem $6($at the bottom$)$ and calculate the horizontal effective stress at point A$.$ The lateral stress ratio of the sand layer is $0\mathrm{.}4$ and that of the clay layer is $0\mathrm{.}5.$ Ans $=65$ kPa.

$6.$ A site is underlain by two soil layers over bedrock. The unit weights of the top $($sand$)$ layer are $19$ and $21$ kN$/$m$^3$ and the layer is $6$ meters thick. The unit weights of the bottom $($clay$)$ layer are $20$ and $22$ kN$/$m$^3,$ and the layer is $8$ meters thick. The water table is located $2$ meters below the ground surface. Important: when two unit weights $($or densities$)$ are given for a soil, then one is the dry unit weight and the other is the saturated unit weight. $($a$)$ Draw the profile neatly, add dimensions, and draw a tree on the ground surface. $($b$)$ Determine the vertical total stress at point A$,$ which is located at a depth of $10$m$.($c$)$ Determine the vertical effective stress at a point A$.$