A production process at Kenneth Day Manufacturing is shown in the figure below. The drilling operation occurs separately$$ from, and simultaneously$$ with, the sawing and sanding operations. A product needs to go through only one of the three assembly operations$($the operations are in$$ parallel$).$

font size decreased by $1$ Bold AssemblyAssembly font size decreased by $1$ Bold AssemblyAssembly font size decreased by $1$ Bold AssemblyAssembly

Sanding

Drilling

Welding

$7$ units$/$hr

$6$ units$/$hr

$2\mathrm{.}5$ units$/$hr

$0\mathrm{.}8$ units$/$hr

$0\mathrm{.}8$ units$/$hr

$0\mathrm{.}8$ units$/$hr

$1\mathrm{.}8$ units$/$hr

Sawing

A figure has seven rectangles. The first rectangle is labeled "Sawing, $1\mathrm{.}8$ units per hour". The second and third rectangles are parallel and arranged vertically, with the second being on top and the third being on the bottom. An arrow points from the first rectangle to the second rectangle. The second rectangle is labeled "Sanding, $7$ units per hour". The third rectangle is labeled "Drilling, $6$ units per hour". An arrow points from the second and third rectangles to the fourth rectangle. The fourth rectangle is labeled "Welding, $2\mathrm{.}5$ units per hour". The fifth, sixth, and seventh are arranged vertically, with the fifth being on top, the sixth being in the middle, and the seventh being on the bottom. An arrow points from the fourth rectangle to the fifth, sixth, and seventh rectangles. The fifth rectangle is labeled "Assembly, $0\mathrm{.}8$ units per hour". The sixth rectangle is labeled "Assembly, $0\mathrm{.}8$ units per hour". The seventh rectangle is labeled "Assembly, $0\mathrm{.}8$ units per hour".

Part $2$

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is the bottleneck LOADING... $.$