I am a common factor of 30 and 60. I am a multiple of 3 and 10. I am greater than 6. What number am I?
Factors of 30: 1, 2, 3, 5, 6, 10, 15, 30
Factors of 60: 1, 2, 3, 4, 5, 6, 10, 12, 15, 20, 30, 60
Highest common factor of 30 and 60: 30
Multiples of 3: 3, 6, 9, 12, 15, 18, 21, 24, 27, 30
Multiples of 10: 10, 20, 30
Lowest common multiple of 3 and 10: 30
The number is 30.
Answer(s): 30