I am a common factor of 20 and 30. I am a multiple of 2 and 10. I am greater than 9. What number am I?
Factors of 20: 1, 2, 4, 5, 10, 20
Factors of 30: 1, 2, 3, 5, 6, 10, 15, 30
Highest common factor of 20 and 30: 10
Multiples of 2: 2, 4, 6, 8, 10
Multiples of 10: 10
Lowest common multiple of 2 and 10: 10
The number is 10.
Answer(s): 10
