I think it's a valid question. I believe he's asking if he should use 3.2, or say, 3:12.
I use the decimal system, because that's what I had been using since my first flight lesson. The first airline I flew for had a minute-to-decimal conversion table in their GOM. It's kind of funny that after converting all of the times to decimals using their table, the decimal times were always a little bit less than the minute times after you started adding them up.