I want to ask your opinion, my mother is 75 years old - which hairstyle suits her

 

This is a classic trick question 

*Answer: 13 people*

Here's why:

- *1* dad

- *11* sons 

- *1* sister that all 11 sons share

"Each son has _a_ sister" doesn't mean each son has a _different_ sister. They all have the same one sister.

So 1 + 11 + 1 = *13*

Did that one get you or did you see it right away?