2012 · Q31
Let x in {2, 3, 4} and y in {4, 6, 9, 10}. Let A be the set of all ordered pairs (x, y) such that x is a factor of y. How many elements does the set A contain?
Elementary MathematicsNumber System
- A12
- B10
- C7
- D6
Explanation
Pairs: (2,4),(2,6),(2,10),(3,6),(3,9),(4,4) - six in all.