Определить период

...

How many working days in year 1990?

Here is the detail of the calculation:

Because 1990 is not a leap year, it has 365 days.

Let's remove 52 saturdays and 52 sundays. It remains 261 days.

Now, let's remove 9 public holidays that do not fall during a weekend and we obtain 252 working days in 1990.

Here is the list of these 9 public holidays:

1. New Year's Day : понедельник, 1 январь, 1990
2. Maundy Thursday : четверг, 12 апрель, 1990
3. Good Friday : пятница, 13 апрель, 1990
4. Easter Monday : понедельник, 16 апрель, 1990
5. General Prayer Day : пятница, 11 май, 1990
6. Ascension Day : четверг, 24 май, 1990
7. Whit Monday : понедельник, 4 июнь, 1990
8. Christmas Day : вторник, 25 декабрь, 1990
9. Boxing Day : среда, 26 декабрь, 1990

And here are the 2 public holidays falling on a weekend:

1. Easter Sunday : воскресенье, 15 апрель, 1990
2. Pentecost : воскресенье, 3 июнь, 1990