It's probably not too bad of a conversion, however, given the fact that the number of times you pause (amount of time it is paused), load, and re-load, are all not accounted for in the timing. It depends on how good you are at the game, how many chances you take, whether you did a normal install, etc.
I made it through the game once in 45 days. That would roughly count as 4.5 days of real time (direct 1/10 conversion), or 108 hours of playing time. It's about right, I think.
"But I also made it clear to [Vladimir Putin] that it's important to think beyond the old days of when we had the concept that if we blew each other up, the world would be safe." -President George W. Bush, Washington, D.C., May 1, 2001