A project has the following activities, precedence relationships, and time estimates in weeks:

Activity	Immediate Predecessor Activities	Optimistic Time (to)	Most Likely Time (tm)	Pessimistic Time (tp)
A	--	15	20	25
B	--	8	10	12
C	A	25	30	40
D	B	15	15	15
E	B	22	25	27
F	E	15	20	22
G	D	20	20	22

a. Determine the critical path and the expected duration of the project.

b. What is the probability that the project will take less than 57 weeks to complete?

c. What is the minimum time when you are 80% confident that the project will complete?