A $12mm400mm$ steel plate has staggered holes arranged as shown. Use LRFD$.$

Note: $"A"$ and $"B"$ are the last $2$ digits of your student number.

Ex$.$ Student Number ${2019410963}^{?}{A}^{\text{'}\text{'}}=3$;$B=6$

a$.$ Calculate the gross area in $m{m}^2.$

b$.$ Calculate $"$Pu$"$ in KN considering tension failure on gross area.

c$.$ Calculate the distance $"b"$ so that the net area in path $1-2-3-4$ is equal to the net area of patp $1-2-4?$

d$.$ Using the computed value of $"b",$ find and solve for the critical net area.

e$.$ Calculate $"P{u}^{\text{'}}"$ in KN considering tension failure on critical net area.

f$.$ Calculate the maximum safe tensile force Pu that the steel plate could carry?