The rectangular combined footing $(B=2\mathrm{.}5m,L=17m)$ in the illustration below has a thickness of $1\mathrm{.}2m.$ Concrete and soil $($including backfill$)$ have unit weights of $20$ and $24k\frac{N}{m^3},$ respectively.

a$.$ Determine the pressures at Points A and B in the foundation. Note: Don't consider the weight of the soil on the foundation or the columns. Just think about the foundation's weight.

b$.$ How much and which side $($towards A or B$)$ should the foundation dimension be increased in order to have a uniform pressure distribution under the foundation? Determine the uniform pressure in that situation.