An architectural firm offers custom townhouse design packages created by making sequential choices across three stages: Exterior Facade Material (4 choices), Floor Plan Layout (5 choices), and Interior Lighting Scheme (6 choices).
However, two design constraints apply:
1. If the first exterior facade material option is chosen, the fifth floor plan layout option cannot be selected.
2. The sixth interior lighting scheme option can only be selected if the fifth floor plan layout option is chosen.
How many different valid townhouse design packages can a client create?
Cevap: 98 packages
Cevap
The total number of valid townhouse design packages is 98.
The solution splits the decision process into two mutually exclusive scenarios based on whether the 5th layout option is chosen. In Case 1 (5th layout chosen), 3 facade choices × 1 layout choice × 6 lighting choices yields 18 valid packages. In Case 2 (1st through 4th layout chosen), 4 facade choices × 4 layout choices × 5 lighting choices yields 80 valid packages. Adding these mutually exclusive totals gives 18 + 80 = 98 valid design packages.
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Anahtar Kavram
Fundamental Counting Principle with Constrained Cases