Define a period

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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 : Thursday, 27 March, 1975
2. Shvi'i shel Pesach : Wednesday, 2 April, 1975
3. Yom Ha-Atzmaut : Wednesday, 16 April, 1975
4. Rosh Hashanah : Sunday, 7 September, 1975
5. Yom Kippur : Monday, 15 September, 1975

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

1. Shavuot : Friday, 16 May, 1975
2. Rosh Hashanah : Saturday, 6 September, 1975
3. Sukkot : Saturday, 20 September, 1975
4. Shemini Atzeret / Simchat Torah : Saturday, 27 September, 1975