$4$ points possible $($graded$)$

In a ski production center, we are looking at a certain processing line where skis are given the finishing touch to give them sharp edges.

This is done in a $3-$step grinding process.

$--$ First, the edges are given a Rough Grinding,

$--$ then a Medium Grinding.

$--$ and then every ski is given an optimal edge with a careful Fine Grinding.

The processing times are:

$--$ Rough Grinding: $5mi\frac{n}{u}$nit

$--$ Medium Grinding: $7$ min$/$unit

$--$ Fine Grinding: $11mi\frac{n}{u}$nit

Please answer the questions below. $($Note: We assume unlimited resources and unlimited demand$)$

What is the bottleneck of this processing line?

Rough Grinding

Medium Grinding

Fine Grinding

What is'the capacity of the medium grinding process in skis$/$hour$?$ Remember, the processing time for Medium Grinding is $7mi\frac{n}{u}$nit.

$($Round to two decimal places. Note the answer is in skis$/$hour$,$ not skis$/$minute$).$

$5\mathrm{.}45$ skis$/$hour

$12\mathrm{.}00$ skis$/$hour

$8\mathrm{.}57$ skis$/$hour