Normal Crash Normal Crash Crashing Activity MTR Predecessor(s) Time time cost cost cost/week - A 7 4 20000 38000 3 6000 - B 8 5 50000 74000 3 8000 C 9 7 80000 110000 A 2 15000 A, B D 8 8 30000 30000 0 B E 9 8 10000 12000 1 2000 C F 10 8 90000 124000 2 17000 D, E G 5 5 25000 25000 0 E H 10 8 32000 40000 2 4000 I 5 4 28000 35000 F, G 1 7000 Sum = 365,000 Paths Path time A - C - F - I 31 Critical path A - D - G - I 25 B - D - G - I 26 Normal project time = 31 weeks B - E - G - I 27 Normal project cost = 365,000 B - E - H 27 Activity to crash = A among the critical activities (A, C, F, I) the crashing cost/week for A is the smallest. – Weeks to crash = Minimum{MTR of A, Project time time of second longest path} – i.e. = Minimum{3, 31-27} = 3 Project time after crashing A 3 weeks = 31 3 = 28 weeks – Project cost after crashing A = 365,000 + 3 x 6,000 = 383,000 5. (a) Activity Successors(s) A C, D B D, E C F D G E G, H F I G I H Finish I Finish (b)
Activity Normal Time Crash time Normal cost Crash cost MTR Crashing cost/week Predecessor(s) A 7 4 20000 38000 3 6000 - B 8 5 50000 74000 3 8000 - C 9 7 80000 110000 2 15000 A D 8 8 30000 30000 0 A, B E 9 8 10000 12000 1 2000 B F 10 8 90000 124000 2 17000 C G 5 5 25000 25000 0 D, E H 10 8 32000 40000 2 4000 E I 5 4 28000 35000 1 7000 F, G Sum = 365,000 Paths Path time A - C - F - I 31 Critical path A - D - G - I 25 Normal project time = 31 weeks Normal project cost = 365,000 B - D - G - I 26 B - E - G - I 27 B - E - H 27 Activity to crash = A – among the critical activities (A, C, F, I) the crashing cost/week for A is the smallest. Weeks to crash = Minimum{MTR of A, Project time – time of second longest path} i.e. = Minimum{3, 31-27} = 3 Project time after crashing A 3 weeks = 31 – 3 = 28 weeks Project cost after crashing A = 365,000 + 3 x 6,000 = 383,000 5. (a) Activity Successors(s) A C, D B D, E C F D G E G, H F I G I H Finish I Finish (b)
Fa11-3110-StudyGuide-e1.docx