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 if this project is managed using critical chain methodology?

$9\mathrm{.}0$

$7\mathrm{.}5$

$4\mathrm{.}5$

$6\mathrm{.}0$