> Sadly, overnight the version control system crashes and they have to recover from the previous day's backup. You have lost an entire day's work. If I give you the diff, how long will it take you to type the changes back into the code base and recover your six-hours' work?

I accidently deleted about 2 weeks of my work once. I was a junior dev and didn't really understood how svn works :). It took about 2 days to finish the job, but I had no diff and it wasn't 100% ready, so after recreating what I had I still had to spend about a day to finish it.

TL;DR: I think 11/12th is a reasonable estimate.