GATE 2024 MN – Question 20
The project network is shown. Activities A, B, C, D, E have durations 5, 6, 8, 3, 4 weeks and crash costs 4, 2.5, 2, 3, 4 lakh rupees/week respectively. Find the least cost to shorten the project by one week.
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Show answer and explanation
Correct answer: (B) 2.5
Explanation
The A–B–D–E path takes 5+6+3+4=18 weeks, while A–C–E takes 17. On the critical path B has the lowest one-week crash cost, 2.5 lakh. Crashing B makes both paths 17 weeks and shortens the project by one week. Thus B; cheaper activity C is initially noncritical.