21. Recently, you were assigned to manage a project to remodel the seminar room for your company. You have constructed a network diagram depicting the various activities in the project (Figure 7.13). In addition, you have asked your team to estimate the amount of time that they would expect each of the activities to take. Their responses are shown in the following table:a. What is the expected completion time of the project?b. What is the probability of completing the project in 21 days?c. What is the probability of completing the project in 17 days?