Answer:
The answer is 12.
Explanation:
You would multiply each of them by 12 to get rid of all of the fractions.
This is because 12 is the least common multiple of the denominators. You can find that by lining up their multiples and looking for the one that is the smallest that they have in common.
3: 3, 6, 9. 12. 15
4: 4. 8. 12. 16, 20
6: 6. 12. 18. 24. 30