Consider a bar that operates between $5$pm and $3$am$.$ The demand rate is variable, and can be

described as follows:

$$ Between $5$pm and $9$pm$,$ the demand rate is $100$ customers$/$hr

$$ Between $9$pm and $11$pm$,$ the demand rate is $200$ customers$/$hr

$$ Between $11$pm and $1$am$,$ the demand is constant and equal to $50$ customers$/$hr

$$ After $1$am$,$ no new customer arrives

To serve this demand, the bar has bartenders that work on different shifts. The restaurant

knows that each bartender has a capacity of $50$ customers$/$hour$.$ Suppose that the bartenders

can serve customers in parallel. In addition, we know that:

$$ Between $5$pm and $8$pm$,$ there is only one bartender working at the restaurant

$$ After $8$pm$,$ and until the bar closes, there are two bartenders working in parallel