$(10$ marks$)$ For the retaining wall given in the figure, calculate the factor of safety against sliding, overturning and base pressure. Note that factor of safety for overturning, sliding are base pressure are $1\mathrm{.}5,1\mathrm{.}3$ and $2\mathrm{.}0,$ respectively. Use Rankine method to calculate the active thrust. The safe bearing capacity of soil is $20$kPa.

Foundation base $c=10\frac{t}{m^2},=23,=1\mathrm{.}9\frac{t}{m^3}$

$\frac{2}{6}$