Chapter $2$ Problem solving #$16($p$\mathrm{.}40)$

Q$.$ Consider the baggage check$-$in process of a small airline. Check$-$in data indicate that from $9$ a$.$m$.$ to $10$ a$.$m$.,240$ passengers checked in$.$ Moreover, based on counting the number of passengers waiting in line, airport management found that the average number of passengers waiting for check$-$in was $30.$

How long did the average passenger have to wait in line?