Historical story

What day of the week was 10th April 1949?

To find the day of the week for a given date, you can use Zeller's congruence:

```

h = (q + (13*(m+1)/5) + K + (K/4) + (J/4) - 2*J) mod 7

```

where

* h is the day of the week (0 = Sunday, 1 = Monday, ..., 6 = Saturday).

* q is the day of the month.

* m is the month (3 = March, 4 = April, ..., 12 = December). If the month is January or February, then you need to increment the year and use m = 11 or m = 12, respectively.

* K is the year of the century (the last two digits of the year).

* J is the century (the first two digits of the year).

```

For April 10, 1949:

* q = 10

* m = 4

* K = 49

* J = 19

```

```

h = (10 + (13*(4+1)/5) + 49 + (49/4) + (19/4) - 2*19) mod 7

h = (10 + (13*5)/5 + 49 + 12 + 4 - 38) mod 7

h = (10 + 26 + 49 + 12 + 4 - 38) mod 7

h = 63 mod 7

h = 0

```

Therefore, April 10, 1949 was a Sunday.