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GATE 2016 CE (CE2) – Question 20

Construction Management · Project planning and scheduling: AOA and AON, PERT and CPM · 1 mark · Multiple choice

A construction project has twelve activities. Durations (days): A inauguration 1; B foundation work 7; C structural construction-1 30; D structural construction-2 30; E brick masonry 25; F plastering 7; G flooring 25; H electrification 7; I plumbing 7; J woodwork 7; K coloring 3; L handing over 1. The network is shown. Total floats for activities 5–7 and 11–12, respectively, are ______ days.

Diagram for GATE 2016 CE (CE2) question 20
  1. 25 and 1
  2. 1 and 1
  3. 0 and 0
  4. 81 and 0

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Show answer and explanation

Correct answer: (C) 0 and 0

Explanation

Earliest events after A and B occur at1 and8days; both30-day construction branches reach38. The upper route E,F,J takes25+7+7=39days, and the lower G,H,I also takes39, so event10 occurs at77. K and L finish at80 and81. Backward calculation puts both5–7 and11–12 on critical paths, so each total float is **0days, C**.