Source: Extra Practice
If the set A has 3 elements and the set B = {3, 4, 5}, then the number of elements in (A × B) is:
Options
Option A
3
Option B
6
Option C is correct
9
Option D
27
Explanation
The number of elements in the Cartesian product A × B is given by n(A × B) = n(A) × n(B). Here, n(A) = 3 and B = {3, 4, 5} so n(B) = 3. Therefore, n(A × B) = 3 × 3 = 9. Option B incorrectly adds the counts. Option D treats it as 3^3.