Please read the following table in Markdown format and then answer the question according to the table. Table cells in one row are seperated by '|', and different rows are seperated by '
'.

Table:
| School | City | Team Name | Enrollment 08-09 | IHSAA Class | County | Year Joined | Previous Counference |
| --- | --- | --- | --- | --- | --- | --- | --- |
| Hammond Bishop Noll | Hammond | Warriors | 453.0 | 2A | 45 Lake | 2007 | Lake |
| Calumet | Calumet Township | Warriors | 640.0 | 3A | 45 Lake | 2007 | Lake |
| Lake Station Edison | Lake Station | Fighting Eagles | 425.0 | 2A | 45 Lake | 2007 | Lake |
| Marquette Catholic | Michigan City | Blazers | 161.0 | A | 46 LaPorte | 2007 | Independents |
| North Newton | Morocco | Spartans | 480.0 | 2A | 56 Newton | 2007 | Independents |
| River Forest | Lake Station | Ingots | 426.0 | 2A | 45 Lake | 2007 | Independents |
| South Central (football only) | Union Mills | Satellites | 297.0 | A | 46 La Porte | 2007 (fb) | N/A |
| Wheeler | Union Township | Bearcats | 564.0 | 2A | 64 Porter | 2007 | Lake |
| Whiting | Whiting | Oilers | 310.0 | 2A | 45 Lake | 2007 | Lake |
Question:
What is the average enrollment 08=09, for the team that had a previous conference of lake and IHSAA class of 3A?
Answer:
640.0