A PERT network has three activities on critical path with mean time 3, 8 and 6 and standard deviations 1, 2 and 2 respectively. The probability that the project will be completed in 20 days is
A. 0.50
B. 0.66
C. 0.84
D. 0.95
Answer: Option C
Solution (By Examveda Team)
Standard deviation = square root of (variance) = square root of (1 * 1 + 2 * 2 + 2 * 2) = square root of (9) = 3D = 20
S = 3 + 8 + 6 = 17
Probability $$ = \frac{{\left( {{\text{D}} - {\text{S}}} \right)}}{{{\text{standard deviation}}}} = 1$$
Now, from Z table probability = 0.84.
This Question Belongs to Mechanical Engineering >> Industrial Engineering And Production Management
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