A construction project is broken down into the following 10 activities:

ACTIVITY IMMEDIATE PREDECESSOR TIME (WEEKS)
1 — 5
2 1 2
3 1 5
4 1 6
5 2, 3 5
6 3 5
7 4 2
8 5 5
9 6, 7 6
10 8, 9 4

a. What is the critical path?
b. How many weeks will the project take to complete?
c. If activities 1 and 10 cannot be shortened, but activities 2 through 9 can be shortened to a minimum of one week each at a cost of $10,000 per week, which activities would you shorten to cut the project by four weeks?