Answer:
85
Explanation:
The number you Add with goes up by 2 with each equation. Since five is the first number,
5+3=8 (Pattern #2)
8+5=13 (Pattern #3)
13+7=20 (pattern #4)
20+9=29 (pattern #5)
29+11=40 (pattern #6)
40+13= 53 (pattern #7)
53+15=68 (pattern #8)
68+17=85 (pattern #9)