Answer:
20
Explanation:
To get to -10 from 5 you have to subtract 15
to get to 20 from -10 you have to add 30
Repeat that process until you get to the 6th term.
5 (1st term)
5 - 15 = -10 (2nd term)
-10 + 30 = 20 (3rd term)
20 - 15 = 5 (4th term)
5 + 30 = 35 (5th term)
35 - 15 = 20 (6th term)