I dont know how to slove it

5. (a) (b) (c) (d) (23 marks} The table below shows the activities, their immediate predecessors and activity time estimates (in days) of a project. Activity Immediate Optimistic Most Pessimistic Predecessor Probable A - 1 3 11 B - 4 6 3 C A 2 3 10 D B 5 8 17 E A1 B E 8 16 F C, E 3 5 7 G C, D r 15 1? Determine mean time and variance for each activity and complete the following table. Activity Mean Time Variance A B C D E F G Construct a complete project network for the project Dene the random variable T = completion time of the project. Find the mean and the standard deviation of T. What is the probability that the project is completed in 25 days? Suppose the {mean} times of D, E, F and G can be each cut down to 7 days, 6 days, 4 days and 11 days respectively, with crash costs of $100, $120, $140 and $125 per day respectively. Formulate a linear program to minimize the project completion time at a budget of $4200