$\backslash$table$[[$Activity$,$Predecessors,Duration$($weeks$),$Budget $($$$)],[$A$,-,6,900],[$B$,-,6,1200],[$C$,$A$,6,1200],[$D$,$A$,12,1800],[$E$,$B$,$C$,14,1400],[$F$,$B$,$C$,$D$,10,1500],[$G$,$D$,$E$,16,800]]$

$4$a$.(20$ points$)$ Draw the network with AOA $($AON is not evaluated$).$ Find the critical path and the duration of the project.

$4$b$.(15$ points$)$ At week $24$ of a project to shoot a TV commercial, what should the expenditures be$?$ If the earned value is right on schedule but the actual expenses are $$9,000,$ what are the cost and schedule variances? What are the EAC and the ETC?

ETC$=$EAC$-AC$;EAC$=BA\frac{C}{C}\frac{?}{PI}$ ;$SV=BCWP-BCWS$;$CV=BCWP-$ACWP;$\frac{C}{P}$I $=BCW\frac{P}{A}C\frac{S}{P}$I $=BCW\frac{P}{B}CWS$