If 2+2=5, 3+3=7 and 4+4=9 then 5+5=?

Question

If

2    3 = 9
5    4 = 26
6    2 = 13

Then

7    4 = ??

Answer 1

5 + 5 = 11

Recall

2 + 2 = 5
3 + 3 = 7
4 + 4 = 9

Its clear that
n + n = 2n + 1

so

5 + 5 = 11