$\backslash$table$[[$Activity$,$Predecessor$($s$),$Duration $($days$)],[$A$,-,5],[$B$,$A$,20],[$C$,$A$,15],[$D$,$A$,5],[$E$,$B$,$ C$,60],[$F$,$D$,15],[$G$,$E$,20],[$H$,$E$,15],[$I$,$F$,$ G$,$ H$,2]]$

Figure $7-6$ Network Scheduling Data

Consider the network scheduling data presented in Figure $7-6.$ How many days of slack are associated with activity F$?$