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Zorluk: OrtaOverlapping Sets and Venn Diagrams

An automotive testing center evaluated 350350 electric vehicle models for three advanced driver-assistance features: Lane Keeping Assist (LL), Automatic Emergency Braking (AA), and Blind Spot Detection (BB). The evaluation showed that 180180 models had feature LL, 150150 had feature AA, and 160160 had feature BB. Additionally, 6565 models had both LL and AA, 5050 had both AA and BB, 6060 had both LL and BB, and 2525 models had all three features. How many of the evaluated electric vehicle models had none of these three features?

Cevap: 10 models

Cevap

The number of electric vehicle models that had none of the three features is 10.
Using the formula for three overlapping sets, LAB=L+A+B(LA+AB+LB)+LAB|L \cup A \cup B| = |L| + |A| + |B| - (|L \cap A| + |A \cap B| + |L \cap B|) + |L \cap A \cap B|, we get 180+150+160(65+50+60)+25=340180 + 150 + 160 - (65 + 50 + 60) + 25 = 340 vehicles with at least one feature. Subtracting this from the total evaluated group of 350350 yields 350340=10350 - 340 = 10 vehicles with none of the features.

Adım Adım Çözüm

1
Use the Principle of Inclusion-Exclusion for three overlapping sets to find the total number of models with at least one feature.
LAB=180+150+160(65+50+60)+25=340|L \cup A \cup B| = 180 + 150 + 160 - (65 + 50 + 60) + 25 = 340 models.
Adding individual set counts overcounts pairwise overlap regions twice and the central triple overlap three times. Subtracting pairwise intersections corrects for double counting, and adding back the triple intersection accounts for its over-subtraction.
2
Subtract the number of models having at least one feature from the total number of tested models.
None=350340=10\text{None} = 350 - 340 = 10 models.
The entire group consists of models with at least one feature plus models with none of the features.

Anahtar Kavram

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