Answer:
29
Explanation:
From 2 to 9, it's adding 7.
From 9 to 11, it's adding 2.
and so forth with the rest of them
11-18: 7
18-20: 2
20-27: 7
so it's a pattern rotating by adding 7 then by adding 2
so from 20 to 27, we added 7, so now you need to add 2.
27 + 2 = 29
so your answer is dun dun dun '29'