Respuesta :

15. 11/21
16. 4/15
17. 1/24
18. 1 11/20
19. 6 13/15
20. 3 1/42
15. 11/21
16. 4/15
17. 1/24
18. 31/20 (or) 1 11/20
19. 103/15 (or) 6 13/15
20. 127/42 (or) 3 1/42
Hope this helps! Let me know if you need any further assistance!