If n(U) = 700, n(A) = 200, n(B) = 300 and n(A ∩ B) = 100, then n(A' ∩ B') is:
Answer: C
Using De Morgan's Law, we know that A' ∩ B' = (A ∪ B)'.
Therefore, n(A' ∩ B') = n((A ∪ B)') = n(U) - n(A ∪ B).
First, we find n(A ∪ B):
n(A ∪ B) = n(A) + n(B) - n(A ∩ B) = 200 + 300 - 100 = 400.
Now, n(A' ∩ B') = n(U) - 400 = 700 - 400 = 300.