Use the text below to answer the next three questions:

On average, $5$ students enter the campus cafeteria every minute. $10\%$ of the students that enter the cafeteria see a long line and leave without entering the line. Note: The "line" is considered the process, so if a student doesn't enter the line then they are not considered in the process.

On average, $18$ students are waiting in line and we can assume that any student that enters the line will not leave.

Question $5$

$1$ pts

On average, what is the inventory, I $($number of flow units, students$),$ of the line$/$process$?$

$1\mathrm{.}8$

$4$

$3$

$18$