1. The Durango Paper Company has identified eight activities that need to be completed in order to comply with new EPA air emission standards. Information about these activities are shown below. 

Activity	Description	Immediate Predecessor	Average Time (weeks)
A	Build internal components	--	2
B	Modify roof floor	--	3
C	Construct air stack	A	2
D	Pour concrete frame	A,B	4
E	Build high temp. burner	C	4
F	Install control systems	C	3
G	Install air pollution device	D,E	5
H	Inspect/test	F,G	2

a. Draw a network diagram that represents this project (use Activity on Node convention):

b. Identify all paths and path durations.

c. Indicate the critical path(s) and activities.

2. The project manager at Durango Paper Company wants to know the probability of completing this project in 15 weeks or less. The following additional information has been collected:

Activity	Optimistic Time	Likely Time	Pessimistic Time
A	1	2	3
B	2	3	4
C	1	2	3
D	2	4	6
E	1	4	7
F	1	2	9
G	3	4	11
H	1	2	3

3. Durango Paper Company has been given 12 weeks to install air pollution equipment or face a court-ordered penalty of $1500 per week beyond 12 weeks. Using the following, identify what activities should be crashed each week and how many weeks should be crashed to minimize total costs.