can someone explain the difference between ( ) and w/o it. i probably missed something in previous lessons

Hi I'm interested & i live in NYC!

i thought about it this way down below. somehow i got my answer correct using this logic. i've used And/OR to help me. can someone tell me if my logic makes sense?

/C and P>>T

/P > H

Contrapositive:

/T > C OR /P >H