So that means, when Mansukh was born- Baa was 15..Let's take Mansukh to have married at 22, that makes Baa 37 at the time of Mansukh's marriage..
Mihir's generation must have been born when Mansukh was 24...Mihir got married when he just completed his MBA- at 24..that means..he married Tulsi when he was 25..that time,Mansukh was 48 and Baa was 61!
Twenty years leap,it all fits in!!
Mihir is 44,
Mansukh was 68
and Baa was 81:)
It actually is NOT sick...it does happen.Even today in India,if you visit a hardcore Gujarati household, you will find a Baa living with a minimum of 4 generations:)