Questions #$2,$ #$3,$ #$4$ are about the following situation.

The process for an automated car wash has the following four steps and processing times.

$\backslash$table$[[$Step$,$Time $($min$.)],[$Pre$-$treat,$1],[$Wash$,5],[$Rinse$,2],[$Wax$,3]]$

What is the flow rate of this process?

$15$ cars per hour

$0\mathrm{.}25$ cars per hour

$0\mathrm{.}125$ cars per hour

$12$ cars perhour