Final answer:
To find the number of elements in the intersection of two sets, we use the principle of inclusion-exclusion. Given the number of elements in each set and their union, N(A ∩ B) equals 81.
Step-by-step explanation:
The student is asking a question related to set theory in mathematics, specifically about finding the number of elements in the intersection of two sets given the number of elements in each set and their union. Using the principle of inclusion-exclusion, we can determine N(A ∩ B), which is the number of elements in the intersection of sets A and B. According to this principle, N(A ∩ B) = N(A) + N(B) - N(A ∪ B). Substituting the given values, we get N(A ∩ B) = 431 + 125 - 475, which simplifies to N(A ∩ B) = 81. Therefore, there are 81 elements in the intersection of sets A and B.