please solve by hand

A project is normally expected to be completed after 20 weeks but as you will see later, is required to be crash-completed in 18 weeks. The WBS of the project is as follows: Work Package Normal Completion Fastest Crash Completion Time Cost Duration Cost Predecessor (weeks) ($1,000/week) (weeks) ($1,000/week) 3 20 2 32 B. 18 10 4 24 A 12 10 7 19 A 0 0 5 9 4 12 B,C [a] Create the Activity on Node (AON) network representation of this project. [b] Calculate the slack for each work package. [c] Identify the critical path under normal completion durations. [d] This project will be completed 2 weeks earlier (18 weeks instead of 20 weeks). Create an optimal crash schedule for each work package in the project. Hint: You are allowed to accelerate a task by completing it in between the fastest crash completion time and normal completion time. If you do that, please use linear interpolation to find the cost per week for duration in between normal and fastest crash completion