70% people can's solve this problem.
29.9% people solve this problem. ( ? = 40 ) ; it's correct too, but it's too common answer.
DO you know why the answer is 40 ?
(2+5)+5=12
(3+6)+12=21
(8+11)+21=?
?=40
Top 0.1% people solve this problem. ( ? = 92 ) ; Wow
Do you why?
First, you should think creatively.
you sould think + to ×
(1×4)+1=5
(2×5)+2=12
(3×6)+3=21
(8×11)+4=92
Thanks for watching and solving my writing