Question

The project manager of a task force planning the construction of a domed stadium had hoped to be able to complete construction prior to the start of the next college football season. After reviewing construction time estimates, it now appears that a certain amount of crashing will be needed to ensure project completion before the season opener. Given the following time and cost estimates, determine a minimum-cost crashing schedule that will shave five weeks off the project length. Note: No activity can be crashed more than two weeks.

				CRASHING COSTS
Activity	Immediate Predecessor	Normal Time (weeks)		First Week		Second Week
A	—	12		$15,000		$20,000
B	A	14		10,000		10,000
C	—	10		5,000		5,000
D	C	17		20,000		21,000
E	C	18		16,000		18,000
F	C	12		12,000		15,000
G	D	15		24,000		24,000
H	E	8		—		—
I	F	7		30,000		—
J	I	12		25,000		25,000
K	B	9		10,000		10,000
M	G	3		—		—
N	H	11		40,000		—
P	H, J	8		20,000		20,000
End	K, M, N, P

Crash schedule: (1 week each)

Week 1	Week 2	Week 3	Week 4	Week 5
(Click to select)  C  E  F  E and P  P	(Click to select)  E  E and P  P  C  F	(Click to select)  P  E and P  E  F  C	(Click to select)  C  E and P  F  E  P	(Click to select)  E  E and P  P  F  C

Answer 1

Length after crashing N weeks

Path	N=0	1	2	3	4	5
A-B-K	35
C-E-H-P	44	43	42	42	42	40
C-D-G-M	45	44	43	43
C-E-H-N	47	46	45	45	45	44
C-F-I-J-P	49	48	47	46	45	44

	N=0	1	2	3	4	5
Activity Crashed		C	C	F	F	E,P
Crashing Cost		5000	5000	12000	15000	36000
Total Cumulative cost		5000	10000	22,000	37,000	73,000

Hence, Crash schedule is as follows:

Week 1 - Activity C

Week 2 - Activity C

Week 3 - Activity F

Week 4 - Activity F

Week 5 - Activity E,P