individual possessive

[sitifan]

1. Jim's room and Mary's room
2. Jim's and Mary's room
3. Jim's and Mary's rooms
What's the difference in meaning between the above three expressions?

[2006]

1. Jim's room and Mary's room two separate rooms
2. Jim's and Mary's room Jim and Mary's room
3. Jim's and Mary's rooms Jim and Mary's rooms
What's the difference in meaning between the above three expressions?

look here