if 35+48=40, 23+34=24, 15+25==26 then 11+21=?

Question

If
a/b = 21/34;
b/c = 121/120;
c/d = 17/77;
e/f = 11/15
and
d/e = 14/17
then what is the value of
(abc/def)*2?

Answer 1

35+48=40
3+5+4+8=20
20+20=40

23+34=24
2+3+3+4=12
12+12=24

15+25=26
1+5+2+5=13
13+13=26

11+21=
1+1+2+1=5
5+5=10

Ans is 10

Answer 2

35 + 48 = 40 or (3+5+4+8) x 2 = 40
23 + 34 = 24 or (2+3+3+4) x 2 = 24
15 + 25 = 26 0r (1+5+2+5) x 2 = 26
Then
11 + 21 = ?? (1+1+2+1) x 2 = 10
The answer is 10