The following distribution shows the daily pocket allowance of children of a locality. The mean pocket allowance is Rs.18. Find the missing frequency k.
| Daily pocket allowance (in Rs.) |
11-13 |
13-15 |
15-17 |
17-19 |
19-21 |
21-23 |
23-25 |
| Number of children |
3 |
6 |
9 |
13 |
k |
5 |
4 |
