$($This information applies to questions $9-10)$ In a bicycle factory, frames are defivered to and assembly station $5$ at a time. It takes $15$ minutes for frames to be manufactured and delivered to assembly. Approximately $30$ bicycles are assembled each hour and Demand during the lead time is:

$10\mathrm{.}5$

$450$

$7\mathrm{.}5$

$2$

$15$