Case Problem

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N UCLEAR W ASTE D ISPOSAL AT PAWV P OWER AND L IGHT

PAWV Power and Light has contracted with a waste disposal firm to have nuclear waste from its nuclear power plants in Pennsylvania disposed of at a government-operated nuclear waste disposal site in Nevada. The waste must be shipped in reinforced container trucks across the country, and all travel must be confined to the interstate highway system. The government insists that the waste transport must be completed within 42 hours and that the trucks travel through the least populated areas possible. The following network shows the various interstate segments the trucks might use from Pittsburgh to the Nevada waste site and the travel time (in hours) estimated for each road segment.

The approximate population (in millions) for the metropolitan areas the trucks might travel through are as follows :

City	Population (1,000,000s)	City	Population (1,000,000s)
Akron	0.50	Las Vegas	1.60
Albuquerque	1.00	Lexington	0.50
Amarillo	0.30	Little Rock	0.60
Charleston	1.30	Louisville	0.93
Cheyenne	0.16	Memphis	1.47
Chicago	10.00	Nashville	1.00
Cincinnati	1.20	Oklahoma City	1.30
Cleveland	1.80	Omaha	1.40
Columbus	0.75	Salt Lake City	1.20
Davenport/Moline/		Springfield	0.36
Rock Island	1.00	St. Louis	2.00
Denver	2.20	Toledo	0.76
Des Moines	0.56	Topeka	0.30
Evansville	0.30	Tulsa	1.00
Indianapolis	1.60	Wichita	0.73
Kansas City	2.10
Knoxville	0.54

Determine the optimal route the trucks should take from Pittsburgh to the Nevada site to complete the trip within 42 hours and expose the trucks to the least number of people possible.