The table below gives information about the distance, d d\,d km, cycled by 50 participants in a charity event.
| Distance (d d\,d km) | Frequency |
|---|---|
| 0<d≤100 < d \leq 100<d≤10 | 12 |
| 10<d≤2010 < d \leq 2010<d≤20 | 18 |
| 20<d≤3020 < d \leq 3020<d≤30 | 14 |
| 30<d≤5030 < d \leq 5030<d≤50 | 6 |
Find the class interval that contains the median distance.
Work out an estimate for the mean distance cycled.