I'm too curious to know, how a single .bak file is listing 3 .mdf file.
Have you just made any change to the screen shot of the picture?
Let me know about it
Kumar, instead of waiting hours for the answer from MAK, why not create a database with 3 mdf files and 2 log files and back it up and see the result. since database is empty it should not take more than 1 minute to back it up. It just takes less than 3 minutes to get answer.
Do some R & D and you will get results instantly.