PROBLEM $3(10$ marks$)$

The casting material shown is made of steel having a specific weight of ${}_{st}=80k\frac{N}{\frac{?}{?}}{m}^3.($a$)$ Determine the average compressive stress acting at points A$?($b$)$ Determine the average compressive stress acting at points B$?($c$)$ Draw the stress distribution on the cross section where the points A and B exist? $($d$)$ Draw the stress distribution on the cross section at a depth of $100mm$ and find the average maximum stress