How many relations are there on a set with 5 elements?
Answer and explanation
Correct answer: C. 2^25
- Step 1: A relation is a subset of A × A, which has 25 elements. Step 2. So there are 2^25 relations. Answer: 2^25. Why not the others: 2^5 is what you get if you use 2^n. 5^2 is what you get if you use n². 2^20 is what you get if you count only reflexive relations.
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