part b need to be solved by Julia code

The contractor seeks a way to complete all work in 40 days at least total cost, assuming that the cost of each task is lincarly interpolated for times a job with 7 major tasks. Some of the tasks can begin at any time, but others have predecessors that must be completed first. The following table shows those predecessor task numbers, together with the minimum and maximum time (in days) allowed for each task, and the total cost that would be associated with accomplishing each task in its minimum and maximum times (more time usually saves expense) between the minimum and maximum. (a) Formulate an LP model of this time/cost planning problem using the decision vari- ables (7) s, start time of task) (in days) days to complete task j Min. Max. Cost Cost Predecesser Time Tme Min Max. 6 12 1600 1000 286 2400 1800 3 16 24 2900 2000 4 14 20 1900 1300 5 4 16 3800 2000 6 12 16 2900 2200 7 2 121300 800 Tasks None one Your model should have an objective function summing interpolated cost and main constraints to enforce precedence 1,2 relationships and the time limit b) Enter and solve your model with the class optimization software