Project Management- Precedences; 3 time estimates

The following represents a project that should be scheduled using CPM:
TIMES(DAYS)
ACTIVITY IMMEDIATE PREDECESSORS a m b
A 1 3 5
B 1 2 3
C A 1 2 3
D A 2 3 4
E B 3 4 11
F C,D 3 4 5
II'
G D, E 1 4 6
H F,G 2 4 5
a. Draw the network.
b. What is the critical path?
c. What is the expected project completion time?
d. What is the probability of completing this project within 16 days?