Part $3$:

The following interior activities need to be completed before the new Oil Slick auto service store

can be opened. The contractor is not sure when all the work will be done, but was able to come

up with the following estimates $($in days$).$

Activity predecess

or

optimistic

time

most likely

time

pessimistic

time

A $($install floor$)-----468$

B $($paint$)$ A $151719$

C $($install signs$)$ B $41220$

D $($final

cleaning$)$

C $6810$

If all these remaining activities are critical, what would be the expected completion time, in days,

of the remainder of the project? Path $($A$,$B$,$C$,$D$)$