Draw, in the same diagram, a histogram and a frequency polygon to represent the following data which shows the monthly cost of living index of a city in a period of 2 years:
| Cost of living index |
440 - 460 |
460 - 480 |
489 - 500 |
500 - 520 |
520 - 540 |
540 - 560 |
560 - 580 |
580 - 600 |
| No. of months: |
2 |
4 |
3 |
5 |
3 |
2 |
1 |
4 |
