Find the earliest expected completion date of the project

Question

Critical Path:

The following table provides the optimistic, most likely and pessimistic times for a project which has five activities. Use this information to solve the followings questions.

Activity    Optimistic      Most Likely  Pessimistic    Precedent
A                  3                    4              5                 --
B                  5                    8             12                 A
C                  8                    9             10                 A
D                  1                    2              3                B,C
E                   3                    4              5                 D

Q1. Find the earliest expected completion date of the project

Q2. Find variance for activity C

Q3. Find the variance of critical path

Q4. Find early finish time for activity C