Consider the following work breakdown structure: What is the estimated expected $($mean$)$ time for project completion?

$\backslash$table$[[$Time Estimates $($days$)],[$Activity$,$Precedes,Optimistic,Most Likely,Pessimistic$],[$Start$,$A$,$B$,-,-,-],[$A$,$C$,$D$,44,50,56],[$B$,$D$,45,60,75],[$C$,$E$,42,45,48],[$D$,$F$,31,40,49],[$E$,$F$,27,36,39],[$F$,$End,$58,70,82]]$