You must not have stated the whole problem.
For there are many possibilities. Here are
the ones in which none are over 100 years old.
Kate is 7. Kevin is 6 years younger, or 1. Melanie is 2, which is twice as old as Kevin.
Kate is 8. Kevin is 6 years younger, or 2. Melanie is 4, which is twice as old as Kevin.
Kate is 9. Kevin is 6 years younger, or 3. Melanie is 6, which is twice as old as Kevin.
Kate is 10. Kevin is 6 years younger, or 4. Melanie is 8, which is twice as old as Kevin.
Kate is 11. Kevin is 6 years younger, or 5. Melanie is 10, which is twice as old as Kevin.
Kate is 12. Kevin is 6 years younger, or 6. Melanie is 12, which is twice as old as Kevin.
Kate is 13. Kevin is 6 years younger, or 7. Melanie is 14, which is twice as old as Kevin.
Kate is 14. Kevin is 6 years younger, or 8. Melanie is 16, which is twice as old as Kevin.
Kate is 15. Kevin is 6 years younger, or 9. Melanie is 18, which is twice as old as Kevin.
Kate is 16. Kevin is 6 years younger, or 10. Melanie is 20, which is twice as old as Kevin.
Kate is 17. Kevin is 6 years younger, or 11. Melanie is 22, which is twice as old as Kevin.
Kate is 18. Kevin is 6 years younger, or 12. Melanie is 24, which is twice as old as Kevin.
Kate is 19. Kevin is 6 years younger, or 13. Melanie is 26, which is twice as old as Kevin.
Kate is 20. Kevin is 6 years younger, or 14. Melanie is 28, which is twice as old as Kevin.
Kate is 21. Kevin is 6 years younger, or 15. Melanie is 30, which is twice as old as Kevin.
Kate is 22. Kevin is 6 years younger, or 16. Melanie is 32, which is twice as old as Kevin.
Kate is 23. Kevin is 6 years younger, or 17. Melanie is 34, which is twice as old as Kevin.
Kate is 24. Kevin is 6 years younger, or 18. Melanie is 36, which is twice as old as Kevin.
Kate is 25. Kevin is 6 years younger, or 19. Melanie is 38, which is twice as old as Kevin.
Kate is 26. Kevin is 6 years younger, or 20. Melanie is 40, which is twice as old as Kevin.
Kate is 27. Kevin is 6 years younger, or 21. Melanie is 42, which is twice as old as Kevin.
Kate is 28. Kevin is 6 years younger, or 22. Melanie is 44, which is twice as old as Kevin.
Kate is 29. Kevin is 6 years younger, or 23. Melanie is 46, which is twice as old as Kevin.
Kate is 30. Kevin is 6 years younger, or 24. Melanie is 48, which is twice as old as Kevin.
Kate is 31. Kevin is 6 years younger, or 25. Melanie is 50, which is twice as old as Kevin.
Kate is 32. Kevin is 6 years younger, or 26. Melanie is 52, which is twice as old as Kevin.
Kate is 33. Kevin is 6 years younger, or 27. Melanie is 54, which is twice as old as Kevin.
Kate is 34. Kevin is 6 years younger, or 28. Melanie is 56, which is twice as old as Kevin.
Kate is 35. Kevin is 6 years younger, or 29. Melanie is 58, which is twice as old as Kevin.
Kate is 36. Kevin is 6 years younger, or 30. Melanie is 60, which is twice as old as Kevin.
Kate is 37. Kevin is 6 years younger, or 31. Melanie is 62, which is twice as old as Kevin.
Kate is 38. Kevin is 6 years younger, or 32. Melanie is 64, which is twice as old as Kevin.
Kate is 39. Kevin is 6 years younger, or 33. Melanie is 66, which is twice as old as Kevin.
Kate is 40. Kevin is 6 years younger, or 34. Melanie is 68, which is twice as old as Kevin.
Kate is 41. Kevin is 6 years younger, or 35. Melanie is 70, which is twice as old as Kevin.
Kate is 42. Kevin is 6 years younger, or 36. Melanie is 72, which is twice as old as Kevin.
Kate is 43. Kevin is 6 years younger, or 37. Melanie is 74, which is twice as old as Kevin.
Kate is 44. Kevin is 6 years younger, or 38. Melanie is 76, which is twice as old as Kevin.
Kate is 45. Kevin is 6 years younger, or 39. Melanie is 78, which is twice as old as Kevin.
Kate is 46. Kevin is 6 years younger, or 40. Melanie is 80, which is twice as old as Kevin.
Kate is 47. Kevin is 6 years younger, or 41. Melanie is 82, which is twice as old as Kevin.
Kate is 48. Kevin is 6 years younger, or 42. Melanie is 84, which is twice as old as Kevin.
Kate is 49. Kevin is 6 years younger, or 43. Melanie is 86, which is twice as old as Kevin.
Kate is 50. Kevin is 6 years younger, or 44. Melanie is 88, which is twice as old as Kevin.
Kate is 51. Kevin is 6 years younger, or 45. Melanie is 90, which is twice as old as Kevin.
Kate is 52. Kevin is 6 years younger, or 46. Melanie is 92, which is twice as old as Kevin.
Kate is 53. Kevin is 6 years younger, or 47. Melanie is 94, which is twice as old as Kevin.
Kate is 54. Kevin is 6 years younger, or 48. Melanie is 96, which is twice as old as Kevin.
Kate is 55. Kevin is 6 years younger, or 49. Melanie is 98, which is twice as old as Kevin.
Kate is 56. Kevin is 6 years younger, or 50. Melanie is 100, which is twice as old as Kevin.
Edwin
