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How many working days in year 1975?

Here is the detail of the calculation:

Because 1975 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 5 public holidays that do not fall during a weekend and we obtain 256 working days in 1975.

Here is the list of these 5 public holidays:

1. Pesach : четверг, 27 март, 1975
2. Shvi'i shel Pesach : среда, 2 апрель, 1975
3. Yom Ha-Atzmaut : среда, 16 апрель, 1975
4. Rosh Hashanah : воскресенье, 7 сентябрь, 1975
5. Yom Kippur : понедельник, 15 сентябрь, 1975

And here are the 4 public holidays falling on a weekend:

1. Shavuot : пятница, 16 май, 1975
2. Rosh Hashanah : суббота, 6 сентябрь, 1975
3. Sukkot : суббота, 20 сентябрь, 1975
4. Shemini Atzeret / Simchat Torah : суббота, 27 сентябрь, 1975