An Italian engineering project has the following activities, whose time estimates are listed as follows: What is the planned project duration?

Activity Estimated Duration (in months) Optimistic Most Likely Pessimistic 1-2 2 2 14 1-3 2 8 14 1-4 4 4 16 2-5 12 12 2 3-5 4 10 28 4-6 4 er 10 ursa 16 5-6 6 12 30