The table below shows the results of a survey of 175 students about their preferred school club. If a student is chosen at random from this group, what is the probability that the student's preferred club is either the Art Club or the Debate Club?
| Preferred Club | Number of Students |
|---|---|
| Art Club | 30 |
| Science Club | 45 |
| Debate Club | |
| Sports Club | 50 |
| Total | 175 |