A middle school principal has 80 keys on her key chain to distribute to staff on the first day of school. Of these 80 keys, 60 open classroom doors, 40 open the door to the teachers' lounge, and 30 open classroom doors and the teachers' lounge. Using this information, answer each of the following questions.

Let CCC be the event that a randomly selected key opens a classroom and TTT be the event that a randomly selected key opens the teachers' lounge.

What is P(C)P(C)P, left parenthesis, C, right parenthesis, the probability that a key opens a classroom?