Q90

Find the ??

12 = 18
13 = 34
14 = 38
15 = ??

ANSWER:

12+13 = 18+34

25 =52 (reverse is symetric)

13+14=34+38

27=72 (reverse is symetric)

14+15= 38+??

29 =92 (reverse is symetric)

so 92=38 +??

??=92-38

??=54

15=54

Simple Solution:

12= 18, Reverse 12 then 21-3=18

13=34, Reverse 13 then 31+3=34

14=38, Reverse 14 then 41-3=38

15= ?? Reverse 15 then 51+3= 54