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GATE 2022 CE (CE1) – Question 39

Construction Management · Project planning and scheduling: AOA and AON, PERT and CPM · 2 marks · Multiple choice

The activities are:

ActivityDuration (days)Depends on
P10—
Q12—
R5P
S10Q
T10P, Q

Which combination is correct?

  1. Total duration of the project = 22 days, Critical path is Q → S
  2. Total duration of the project = 20 days, Critical path is Q → T
  3. Total duration of the project = 22 days, Critical path is P → T
  4. Total duration of the project = 20 days, Critical path is P → R

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Correct answer: (A) Total duration of the project = 22 days, Critical path is Q → S

Explanation

The independent starts P and Q finish on days 10 and 12. R finishes on day 15; S on day 22; T cannot start until both P and Q finish, so it also finishes on day 22.

The project duration is **22 days**, with critical routes **Q–S** and **Q–T**. Option **A** gives a correct critical path and duration.