To be completely transparent: this is a homework question that I am requesting help with.
The question says, "The Julian calendar has 365 days unless the year number satisfies x ≅ 0 (mod 4), in which case the year has 366 days".
My understanding so far is that if the year is divisible by 4, it is a leap year and has 366 days.
The question then goes on, "Explain why 11th February in year X of the Julian calendar is a Friday if x ≅ 1732 (mod 28).
Here is what I have so far,
1732 % 28 = 24 X % 28 = 24
[(X % 28) + 4] % 4 == 0
Therefore I know that X is divisible by 4 and is thus a leap year (has 366 days). But what do I do next?