*18. DEF A/C Remodelers has contracted to reconfigure the interior of a large corporate A/C. The project manager has determined that there are 11 steps to the process. In consultation with the project foreman he has determined the sequence and precedent for the 11 events, labeled A – K, and has estimated the optimistic, expected, and pessimistic job times, labeled a, m, and b, respectively. These times, in days, and precedence are given in the table below.
ACTIVITY a m b IMMEDIATE PREDECESSORS
A 3 6 8
B 2 4 4
C 1 2 3
D 6 7 8 C
E 2 4 6 B, D
F 6 10 14 A, E
G 1 2 4 A, E
H 3 6 9 F
I 10 11 12 G
J 14 16 20 C
K 2 8 10 H, I
a. What is the critical path for the installation of the interior?
b. What is the expected completion time, in working days, for the project?
c. What is the probabilityof finishing the project in 40 working days or less?
d. What is the probability of the job taking more than 50 working days?
A step by step solution is provided.