Project Management. Please show full work.

3. In Problem 2, suppose that after digging all sections, plumbing work can be started but only 20% of the job can be completed before any concrete is poured. After each section of the footings is completed, the remaining plumbing work can be started provided that the preceding 20% portion is complete. Construct the project network using an Activity-on-Node (AON) representation. 4. Construct an Activity-on-Arrow (AOA) network for a project comprised of activities A to P that satisfies the following precedence relationships: a. A, B, and C, the first activities of the project, can be executed concurrently. b. D, E, and F follow A. c. I and G follow both B and D. d. H follows both C and G. e. K and L follow I. f. J succeeds both E and H. g. M and N succeed F, but cannot start until both E and I are completed. h. O succeeds M and I. i. P succeeds J, L, and 0. j. K, N, and P are the terminal activities of the project