Question 1
The table shows information about the lengths, in minutes, of 50 telephone calls.
| Length of telephone call (m minutes) | Frequency |
| 0 < m | 8 |
| 5 < m | 2 |
| 10 < m | 6 |
| 15 < m | 4 |
| 20 < m | 12 |
| 25 < m | 18 |
Work out an estimate for the total length, in minutes, of these telephone calls.
(3)