GATE 2022 PI – Question 35
Activities A–G have expected durations 4,5,4,1,7,6,8 minutes and variances 1,1,1,0,4,1,4 respectively. The critical path is B,E,G. Find project-duration standard deviation in minutes to two decimals.
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Correct answer: 2.90 to 3.10
Explanation
Under the PERT independence assumption, critical-path variances add: 1+4+4 = 9 min². Take the square root, giving **3.00 min**. The source labels variance units as minutes; dimensionally they are min².