Student-teacher ratio expresses the relationship between the number of students enrolled in a school and the number of teachers employed by the school. This ratio is important for a number of reasons. It can be used as a tool to measure teachers’ workload as well as the allocation of resources. A survey was conducted in 100 secondary schools of a state and the following frequency distribution table was prepared :
| Number of students per Teacher | Number of Schools |
| 20 - 25 | 5 |
| 25 - 30 | 15 |
| 30 - 35 | 25 |
| 35 - 40 | 30 |
| 40 - 45 | 15 |
| 45 - 50 | 10 |
Based on the above, answer the following questions :