how do i solve problems such as this? if

you could do this one as an example it would be appreciated.

Consider the following PERT/CPM network with estimated times in weeks E Start B 3 A 1 D 2 F 2 7 Finish 4 The three-time estimate approach was used to calculate the expected times and the following table gives the variance for each activity: Activity Variance Activity Variance A 1.5 E 0.3 B 0.5 F 0.6 1.2 G 0.6 D 0.8 H 1.0 Give the expected project completion time, the critical path of the project, and what is the probability that the project will be completed within 19 weeks? The answer should be given in the following format: Expected project completion time; The critical path of the project; The probability that the project will be completed within 19 weeks 15; Start-A-B-D-G-H-Finish: 0.9719 16; Start-A-B-E-F-H-Finish: 0.9357 17: Start-A-B-E-F-H-Finish: 0.8438 15; Start-A-B-D-G-H-Finish; 0.0281 17; Start-A-B-D-G-H-Finish; 0.8289 16; Start-A-B-D-G-H-Finish; 0.9236 15; Start-A-B-E-F-H-Finish; 0.9788 104 ish; 0.9719 O 16; Start-A-B-E-F-H-Finish; 0.9357 017; Start-A-B-E-F-H-Finish; 0.8438 15; Start-A-B-D-G-H-Finish; 0.0281 17; Start-A-B-D-G-H-Finish; 0.8289 16; Start-A-B-D-G-H-Finish; 0.9236 15; Start-A-B-E-F-H-Finish; 0.9788 15; Start-A-B-D-G-H-Finish; 0.8186 AD; 0 B 16; Start-A-B-D-G-H-Finish; 0.0764 O B-- 16; Start-A-B-D-G-H-Finish; 0.7517