Question $27($Mandatory$)(10$ points$)$

le city roads dept. repairs $300,000$ potholes, on average, in a year. Critics allege that the dept. is inefficient, given that an average of $60,000$ unfilled potholes exist on city roads at any given time $($confirmed from official records$).$ The dept. protests the charge, asserting that they fix a pothole, on average, in less than a month. From the numbers provided above, how long does it take the city, on average, to fix a pothole? $($Hint: Little's Law: Average Inventory $=$ Average Flow Rate ${?}^{**}$ Average Flow Time$)$

$0\mathrm{.}59$ months

$6\mathrm{.}40$ months

$1\mathrm{.}32$ months

$2\mathrm{.}40$ months