1. Given the following activity network: Three nodes - A1, A2, A3; two paths - A1, A2 and A1, A3.

Activity A1 takes 5 weeks, A2 takes 7 weeks, and A3 takes 4 weeks with a 50% probability and 10 weeks with a 50% probability. What is the project completion time under the worst-case scenario, that is, A3 is late and takes 10 weeks?

2. A project activity has an earliest completion time of 6, an activity time of 3, and a latest completion time of 8. What is the slack time for the activity?