Assume that a pharmacy opens at

$6$

:

$0$

$0$

am and customers arrive according to a non

$-$

homogeneous Poisson

$\{$

N

$($

t

$)$

$,$

$6$

$<$

$=$

t

$<$

$=$

$2$

$2$

$\}$

$,$

N

$($

$6$

$)$

$=$

$0$

$,$

with theintensity function:

$\backslash$

lambda

$($

t

$)$

$=$

$1$

$0$

$$

$($

$5$

$/$

$4$

$)$

$($

t

$$

$6$

$)$

$6$

$<$

$=$

t

$<$

$=$

$1$

$4$

$$

$($

$5$

$/$

$4$

$)$

$($

t

$$

$1$

$4$

$)$

$1$

$4$

$8$

$|$

N

$($

$2$

$2$

$)$

$>$

$=$

$1$

$\}$

$,$

where S

$1$

$$denotes the arrival time oft he first customer.