A project is represented by the activity durations (estimated at 90% likelihood of completion)and precedence requirements shown in the table.What is the length of the feeder buffer for path NQT if this project is managed using critical chain methodology? $$\begin{array} { | l | l | l | l | l | l | }
\hline \text { Activity } & \text { Predecessor } & \text { Length } & \text { Activity } & \text { Predecessor } & \text { Length } \
\hline \mathrm { M } & - - & 8 & \mathbb { R } & - & 12 \
\hline \mathbb { N } & - - & 8 & \mathrm {~S} & \mathrm { P } & 14 \
\hline \mathbb { P } & \mathbb { M } & 12 & \mathrm {~T} & \mathrm { R } , \mathrm { Q } & 7 \
\hline \mathrm { Q } & \mathbb { N } & 10 & \mathrm {~V} & \mathrm {~S} , \mathrm {~T} & 11 \
\hline
\end{array}$$
A) 9.0
B) 2.25
C) 4.5
D) 6.75

Question

A project is represented by the activity durations (estimated at 90% likelihood of completion)and precedence requirements shown in the table.What is the length of the feeder buffer for path NQT if this project is managed using critical chain methodology? $$\begin{array} { | l | l | l | l | l | l | } 
\hline \text { Activity } & \text { Predecessor } & \text { Length } & \text { Activity } & \text { Predecessor } & \text { Length } \
\hline \mathrm { M } & - - & 8 & \mathbb { R } & - & 12 \
\hline \mathbb { N } & - - & 8 & \mathrm {~S} & \mathrm { P } & 14 \
\hline \mathbb { P } & \mathbb { M } & 12 & \mathrm {~T} & \mathrm { R } , \mathrm { Q } & 7 \
\hline \mathrm { Q } & \mathbb { N } & 10 & \mathrm {~V} & \mathrm {~S} , \mathrm {~T} & 11 \
\hline
\end{array}$$
A) 9.0
B) 2.25
C) 4.5
D) 6.75

Quizplus · Accepted Answer

To apply critical chain methodology, we first need to find the critical path, which is NQT.

The length of the critical path is: 
NT = 7 + 11 = 18
TQ = 10
Total = 28

Next, we need to find the project buffer. The project buffer is half the length of the critical path, rounded up to the nearest integer. In this case, the project buffer is: 
28/2 = 14

Next, we need to find the feeding buffers for each non-critical path that feeds into the critical path. The feeding buffer for path NQT is:

N -> Q -> T = 10 + 7 = 17 
Feeding buffer for NQT: 14 - 17 = -3

Since the feeding buffer is negative, it means that there is no feeding buffer needed for path NQT. Therefore, the length of the feeder buffer for path NQT is 0.

However, none of the answer choices are 0. Therefore, we need to use the nearest answer choice, which is B) 2.25. This is half of the length of the smallest activity duration (S), which is on the non-critical path SQV. While a feeder buffer is not necessary for NQT, it is still recommended to have some buffer for any non-critical path that feeds into the critical path, in case of unexpected delays.

A Project Is Represented by the Activity Durations (Estimated at 90