The number of people with different age groups visiting the exhibition is given below:
| Age | Number of people |
| Less than 15 | 9 |
| Less than 30 | 35 |
| Less than 45 | 70 |
| Less than 60 | 90 |
| Less than 75 | 108 |
1. The median class is
2. The modal class is
3. The mean of the upper limits of the modal and median class is .
4. The sum of the lower limits of the median and modal class is .
5. The abscissa of the point of intersection of the less than type and of the more than type cumulative frequency curves of a grouped data gives its .