Meadows or Malls?
How can we reduce the number of combinations
down from 28?
 Are there any variables that can’t equal 0?
Gd 100 What does this tell you about Gr ?
 From Gr Gd 300 you know that G  200
r
 Can eliminate constraint VII from the list!
How else can we reduce the # of combinations?
Gd
 Constraint II says Ar+Ad=100, and constraint III
syas Mr+Md=150.
o Together, these facts guarantee that
Ad+Md is at most 250.
 But constraint IV says that Gd+Ad+Md is at least
300
o So Gd must be at least 50
 Ignore constraint X
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Ad
 Gd is at least 50
o But constraint VI says Ar+Gd=100
 So Ar must be at most 50
 But constraint II says Ar+Ad=100
o So Ad must be at least 50
 Ignore XI
There are only 10
 I, II, III, VI,
 I, II, III, VI,
 I, II, III, VI,
 I, II, III, VI,
 I, II, III, VI,
 I, II, III, VI,
 I, II, III, VI,
 I, II, III, VI,
 I, II, III, VI,
 I, II, III, VI,
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combinations left!
IV, V
IV, VIII
IV, IX
IV, XII
V, VIII
V, IX
V, XII
VIII, IX
VIII, XII
IX, XII