Question

For the following network determine: 

a) The activities on the critical path 

b) The time for the critical path 

c) The slack for EVERY activity 

Answer 1

step 1

find early start, and early finish from the start of the project for each activity

Activity	Duration, D	Early start, ES=Max of early finish of preceeding activities	Early finish, EF = ES + D
A	5	0	5
B	4	0	4
C	3	5	8
D	6	5	11
E	2	5	7
F	8	11	19
G	5	11	16

step 2	Find Maximum EF = 19 and keep it as the LF of last activities
step 3	calculate LS for each activity after calculating its EF's.

Activity	Duration, D	Early start, ES=Max of early finish of preceeding activities	Early finish, EF = ES + D	Late finish, LF= Min of LS of successor activities	Late start, LS= LF - D	Total slack= LF-EF	Critical activity, activities with 0 slack time
A	5	0	5	5	0	0	Yes
B	4	0	4	5	1	1	No
C	3	5	8	11	8	3	No
D	6	5	11	11	5	0	Yes
E	2	5	7	11	9	4	No
F	8	11	19	19	11	0	Yes
G	5	11	16	19	14	3	No

1. activities on the critical path are A, D and F
2. the time for critical path is 19 (Max of EF's)
3. Slack for every activity is in the table above