Question: how many working days in a week?
Answer: 20 working days would give you 4 weeks (working just Mon-Fri), which is 28 days, and the occasional public holiday. 22 days is more accurate, but if you rely on people producing 22 working days of production every money, you are being optimistic. This leads to 5/7 x 365 working days in a year, which is 261 days.