A PERT Project Has 45 Activities,19 of Which Are on the Critical

Multiple Choice

A PERT project has 45 activities,19 of which are on the critical path.The estimated time for the critical path is 120 days.The sum of all activity variances is 64,while the sum of variances along the critical path is 36.What is the probability that the project can be completed between days 108 and 120?

A) -2.00
B) 0.0227
C) 0.1058
D) 0.4773
E) 0.9773