three of these puzzles have more than one answer. try to find all the possible answers for each puzzle one of these puzzle is impossible.

1.my number is a factor of 20. it's also a factor of 30.
2. my number is a multiple of 10. it's a factor of 45.
3. my number is between 40 and 50. it's a prime.
4. my number is a multiple of 4. it's a square number. it's less than 50.

2 answers

1. Factors of 20 = 1, 2, 4, 5, 10, 20. Factors of 30 = 1, 2, 3, 5, 10, 15, 30

There -- the first one is done for you. If you post your answers to the others, we'll be glad to check them.
2.) 1,9,5, 45

3.) 41, 43 &47

4.) 16