Please show all work, step-by-step please.

Question 5 (35 points). You were recently assigned to manage a project for your company. You have constructed a network diagram (depicting the various activities in the project, see figure below). In addition, you have asked your team to estimate the amount of time (in days) that they would expect each of the activities to take. Their responses are shown in the table below: Start Finish Table 2 - Estimates Data Activity Time Estimates (Days) Optimistic Most Pessimistic Likely B 4 9 14 12 10 a. What is the expected time and variance for each activity? b. What is the expected completion time of the project? c. What is the probability of completing the project in 21 days? d. What is the probability of completing the project in 18 days