Question

P, Q, R, S, and T are the 5 activities along the unique critical path of an AOA network of activities. Their characteristics are as under

$\begin{array}{cccccc}\text{Activity}& \text{P}& \text{Q}& \text{R}& \text{S}& \text{T}\\ \text{Expected}& & & & & \\ \text{duration (days)}& 8& 7& 12& 15& 6\\ \text{Standard}& & & & & \\ \text{deviation (days)}& 3& 3& 4& 5& 2\end{array}$

What is the possible range of project duration (in days)?

• A. 28.12 to 57.91
• B. 24.19 to 71.81
• C. 34.23 to 47.21
• D. 25.50 to 60.51

Answer 1

The correct option is B 24.19 to 71.81

Project duration $=8+7+12+15+6=48$ days

${\sigma }_{project}=\sqrt{3^2+3^2+4^2+5^2+2^2}$

$=7.937$ days

Possible range of project duration $=T_e\pm 3\sigma$

$=(48-3\times 7.937).(48+3\times 7.937)$

$=\left(24.189\right).\left(71.811\right)$

$=(24.189,71.811)$