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Zorluk: Çok zorLogical Venn Diagrams

In a state administrative audit of 300300 urban development projects, participation across three infrastructure domains—Sanitation (SS), Transport (TT), and Green Space (GG)—was analyzed. The audit revealed that 145145 projects involve Sanitation, 135135 involve Transport, and 125125 involve Green Space. Exactly 7070 projects involve precisely two domains, while 2020 projects involve all three domains. Furthermore, 4545 projects involve both Sanitation and Transport, and 3535 projects involve both Transport and Green Space. Which of the following statements are correct? (Select all correct options.)

  1. Exactly 7070 projects are dedicated exclusively to Sanitation.Cevap
  2. The total number of projects involving at least two domains is 9090.Cevap
  3. The number of projects involving both Green Space and Sanitation, but not Transport, is 3030.Cevap
  4. D
    Exactly 1515 projects are not affiliated with any of the three domains.

Cevap

The statements asserting that exactly 70 projects are dedicated exclusively to Sanitation, that 90 projects involve at least two domains, and that 30 projects involve both Green Space and Sanitation but not Transport are all correct.
The three correct options accurately reflect the regional values obtained from set decomposition: exclusive Sanitation projects equal 70, projects in two or more domains total 90 (70 + 20), and projects in Green Space and Sanitation only total 30.

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1
Calculate the regions involving exactly two domains
Sanitation and Transport only = 4520=2545 - 20 = 25; Transport and Green Space only = 3520=1535 - 20 = 15. Green Space and Sanitation only = 70(25+15)=3070 - (25 + 15) = 30.
The intersection of two sets includes the triple intersection of all three sets.
2
Calculate single-domain exclusive regions
Sanitation only = 145(25+30+20)=70145 - (25 + 30 + 20) = 70; Transport only = 135(25+15+20)=75135 - (25 + 15 + 20) = 75; Green Space only = 125(30+15+20)=60125 - (30 + 15 + 20) = 60.
Subtracting all overlapping two-set and three-set regions from each total set size isolates the single-domain counts.
3
Calculate projects in at least two domains
Projects in at least two domains = (Exactly 2 domains) + (All 3 domains) = 70+20=9070 + 20 = 90.
'At least two' is the union of the exactly two and exactly three regions.
4
Calculate total union and unaffiliated projects
Total in at least one domain = 70+75+60+25+15+30+20=29570 + 75 + 60 + 25 + 15 + 30 + 20 = 295. Unaffiliated projects = 300295=5300 - 295 = 5.
Subtracting the union of all three sets from the total project pool yields the count of elements outside all sets.

Anahtar Kavram

Three-Set Venn Diagram Region Decomposition and Inclusion-Exclusion Principle
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