Answer:
1. Not possible
2. Possible
3. 24
4. C
5. D
Explanation:
Some key concepts to remember:
- One -to -one means each element has an element only it matches to. This is only possible when sets have the same number of elements. #1 doesn't but #2 does.
- To determine the number of one-to-one correspondence, use a factorial with the number of elements. 4 is the number and the factorial is 4! = 4*3*2*1 = 24.
- n(A) means the cardinal number of the set or the number of unique elements. Elements count only once even if they repeat. There are 5 in #4 and 12 in #5.