Respuesta :

In Spanish, the words tú and usted  both mean “you". However, tú is much less formal than usted.

So, you 
use tú when you're talking to someone of the same age, the same rank, or the same educational level, but when talking to someone who's considered a high rank, maybe a grandparent, you would use usted.
Tu is you in Spanish and you use it talking to a kid but an older person u use it as an older person