Question

The following table uses the activities in construction projects and relevant information.

Activity	1-2	1-3	2-3	2-4	3-4	4-5
Duration (in days)	22	27	12	14	6	12

Draw the network for the project, calculate the earliest start time, earliest finish time, latest start time, and latest finish time of each activity, and find the critical path. Compute the project duration.

Answer 1

Forward pass:

E₁ = 0

E₂ = 0 + 22 = 22

E₃ = (0 + 27) (or) (22 + 12) = 34 [Maximum of both]

E₄ = (22 + 14) (or) (34 + 16) = 40

E₅ = 40 + 12 = 52

Backward pass:

L₅ = 32

L₄ = 52 – 12 = 40

L₃ = 40 – 6 = 34

L₂ = (40 – 14) (or) (34 – 12) = 22 [Minimum of both]

L₁ = 22 – 22 = 0

EFT and LFT are the same for 1-2, 2-3, 3-4, and 4-5. 

So critical path is 1-2-3-4-5 time to complete is 52 days.