Question

Development of Version 2.0 of a particular accounting software product is being considered by Jose Noquera's technology firm in Baton Rouge. The activities necessary for the completion of this project are listed in the following table: To Cost Normal Time (weeks) Crash Time Normal with Activity (weeks) Cost Crashing Immediate Predecessor(s) $2.700 A $2,000 7 $2,300 S3,100 3 $500 $500 S2,300 $2,580 A E 5900 $1.275 F F $3.400 2 S4,800 C G $1,500 $2.100 D, E a) Based on the given information regarding the activities for the project, the project length weeks b) The total cost required for completing this project on normal time $ c) For reducing the duration of the project by one week, the activity that should be crashed first is activity The cost of the project based on the first activity selected for crashing will increase by S weeks d) The maximum weeks by which the project can be reduced by crashing Total cost of crashing the project to minimum (or maximum weeks possible) $

Answer 1

a)

Based on the given info, the project length is 16 weeks

Activity	Normal	Crash	Normal C	Crash C	IP	Max Crash	Crash slope	Crash time	Final time	Start	Finish	Original CP
A	4	3	2000	3700	-	1	1700	0	4	0	4	Y
B	2	1	2300	3100	-	1	800	0	2	0	2
C	3	3	500	500	-	0	N/A	0	3	0	3
D	8	4	2300	2580	A	4	70	0	8	4	12	Y
E	6	3	900	1275	B	3	125	0	6	2	8
F	3	2	3400	4800	C	1	1400	0	3	3	6
G	4	2	1500	2100	D,E	2	300	0	4	12	16	Y
Normal cost	12900
Crash cost	0

b)

The total cost based on normal time (add up all the normal cost) = 12900

c)

For reducing the project duration by 1 week, we must reduce the critical activity that is the cheapest (smallest crash slope). That is Activity D.

The critical path is A-D-G.

Activity	Normal	Crash	Normal C	Crash C	IP	Max Crash	Crash slope	Crash time	Final time	Start	Finish	Original CP
A	4	3	2000	3700	-	1	1700	0	4	0	4	Y
B	2	1	2300	3100	-	1	800	0	2	0	2
C	3	3	500	500	-	0	N/A	0	3	0	3
D	8	4	2300	2580	A	4	70	1	7	4	11	Y
E	6	3	900	1275	B	3	125	0	6	2	8
F	3	2	3400	4800	C	1	1400	0	3	3	6
G	4	2	1500	2100	D,E	2	300	0	4	11	15	Y
Normal cost	12900
Crash cost	70

d)

Maximum weeks that project can be reduced by crashing is 9 weeks

We can crash A, D, and G to the maximum. This will reduce the path duration to 9 weeks. In addition we need to crash E as well. This will make two critical paths. ADG and BEG

The total cost will be 1290 + 2705 = 3995

Activity	Normal	Crash	Normal C	Crash C	IP	Max Crash	Crash slope	Crash time	Final time	Start	Finish	Original CP
A	4	3	2000	3700	-	1	1700	1	3	0	3	Y
B	2	1	2300	3100	-	1	800	0	2	0	2
C	3	3	500	500	-	0	N/A	0	3	0	3
D	8	4	2300	2580	A	4	70	4	4	3	7	Y
E	6	3	900	1275	B	3	125	1	5	2	7
F	3	2	3400	4800	C	1	1400	0	3	3	6
G	4	2	1500	2100	D,E	2	300	2	2	7	9	Y
Normal cost	12900
Crash cost	2705