What exactly are 16 hour days? how did 2 weeks become equal to 3 and all that-? didn't really get that
Ok, I'll try to explain in the most didactic way possible but please let me know if any part of it is still confusing.
So, per canon, the Ravens operate on 16 hours days. This means that every 16 hours, they start another day in their Raven Calendar. In theory, this means they can cramp their daily routine to be more effective.
How does it work? 24 and 16 actually have very small least common multiples: 24x2=48 and 16x3=48. So in practice, every three Raven Days their timekeeping matches up with Regular Days and that's how they can carry life:
Let's say they begin counting their Raven Hours at Regular Time midnight. First Raven Day ends 16 hours later, 4pm of the First Regular Day, Second Raven Day ends 7am of the Second Regular Day, and Third Raven Day ends midnight of the Second Raven Day, and it all starts again.
So for every two Regular Days, the Ravens actually lived an extra, shorter, one; and this is why Neil feels like he spent three weeks there instead of two. (14 24-hours days vs 21 16-hours days)
Years ago someone made a schedule and technically they could spread their classes just so it would make it possible for them to attend while also living the 16-hours mess, and I fully think this was Nora's intention when she wrote it, but personally I think it's more feasible that they only enter this routine during summer and winter practice, when they're only living among themselves.
In case it helps, here's the schedule I made for my fic that's helping me keep track of stuff: the numbers on the left are the Raven Hours, and the ones in the right are the Regular Hours they match up to in each day
For comparison, in canon the Foxes practiced up to 9 hours a day in the summer, adding 18 hours of practice in two days. Following this schedule, in the same amount of Regular Time the Ravens practiced 21. Now think of this three extra hours every two days for the whole summer. And they don't take weekends off.(spoiler: they practice about 864 hours more in the end)