Is there any simple way to format cells with regards to time?

For example I want to be able to enter 1.3 into a cell and it display 01:30 (meaning 1 hour 30 minutes)
And then if I were to multiply this cell by 2 it would show 03:00 (being 3 hours 0 minutes)

It seems like time formatting on Excel 2010 is very complex, unless it is just me?

thanks for your help.

Alex