Question

QUESTION 5 Given is a CPM project network diagram as shown below. A с F Start E H End B D Start A B E H End Activity day с 7 D 3 F 5 G 6 0 2 4 3 0 a) The Project Completion time = days. b) The Earliest Start time, Es, of Activity G = days. c) The Latest Finish time, LF, of Acitivity C - days. d) The critical activities are (ex. Fill in answer as: ABCD)

Answer 1

ANSWER:

a) The Project Completion time = 24 days
b) The Earliest Start time, ES, of Activity G = 15 days
c) The Latest Finish time, LF, of Activity C = 11 days
d) The critical activities are = ACEGH

CALCULATION:

We calculate the ES, EF, LS, and LF of the given CPM network as below.

On Critical Path? 0 Earliest Latest Earliest Start Latest Finish Slack Activity Time Finish Start ES LF (LF-EF) EF LS A 4 4(= 0+4) 0(= 4-4) 4 [LS(C)] 0 (= 4-4) B 2 0 2 (0+2) 6(= 8-2) 8 (LS(D)] 6 (= 8-2) С 7 4(EF(A)] 11 (= 4+7) 4 (= 11-7) 11 (Minimum {LS(E), LS(F)}] 0 (= 11-11) D 3 2 [EF(B)] 5 (= 2+3) 8 (= 11-3) 11 [LS(E)] 6(= 11-5) E 4 11 (EF(C)] 15 (= 11+4) 11 (= 15-4) 15 [LS(G)] 0 (= 15-15) F 5 11 [EF(C)] 16 (= 11+5) 16 (= 21-5) 21 [LS(H)] 5 (= 21-16) G 6 15 [Maximum {EF(D), EF(E)}] 21 (= 15+6) 15 (= 21-6) 21 [LS(H)] 0 (= 21-21) H 3 21 [Maximum {EF(F), EF(G)}] 24 (= 21+3) 21 (= 24-3) 24 0 (= 24-24) Yes (Slack = 0) No Yes (Slack = 0) No Yes (Slack = 0) No Yes (Slack = 0) Yes (Slack = 0)

Critical path is A->C->E->G->H

Project completion time = Sum of duration of the critical activities = 4+7+4+6+3 = 24 days