5.1 M / G / 1 modified queue Apply (5.2) for the case
of a rectangular (X_{o}byY_{o}) service
region with directions of travel parallel to the sides of the rectangle
and with a single emergency repair unit garaged at the region's center,
(x = X_{o}/2, y = Y_{o}/2). The
emergency repair unit operates as in the third paragraph of Section
5.2.
 Suppose that = 1 call per hour. Let us
examine how several alternative service region designs having equal area
(i.e., X_{o}Y_{o} = A) can affect system
performance. Let A = 4 square miles and response speed be 10
miles/hr. Further, suppose that the mean and variance of onscene
service time are 45 minutes and (45)^{2} minutes^{2},
respectively. Find the mean time from calling until arrival of a service
unit for X_{o} = Y_{o},
X_{o}= 2Y_{o}, and X_{o} =
20Y_{o} (assuming that we constrain
X_{o}Y_{o} = A = 4 square miles). Can the
system be saturated (i.e., > 1) for some values
of X_{o}, Y_{o}, and unsaturated for
others?
 Verify that with the constraint X_{o}Y_{o}
= A, minimum response time is always achieved by setting
X_{o} = Y_{o} = A
