$72\mathrm{.}4$In the ABC machine shop, workers punch in at $8$:$00$ A$.$M$.$ and punch out at $4$:$30$ P$.$M$.$ The labor$-$hanagement agreement allows $30$ min for lunch, which is not counted as part of the $8-$hour shift. In determining the allowance for computing time standards, two $15$ min breaks are provided $($personal time and fatigue$),$ one in the morning and one in the afternoon; and $20$ min have been negotiated as lost time due to supervisor interruptions and equipment malfunctions. What PFD allowance factor should be added to the normalized time to account for these losses in the computation of a standard time, so that if workers work at standard performance, they will produce exactly $8$ standard hours?