From 1955 to 1994 what Fridays were 13th?

Answer 1

There were 540 days whose date was 13. Of these 78 fell on a Friday. These were (in international notation):

13/05/55,

13/01/56, 13/04/56, 13/07/56, 13/09/57, 13/12/57, 13/06/58, 13/02/59, 13/03/59, 13/11/59, 13/05/60,

13/01/61, 13/10/61, 13/04/62, 13/07/62, 13/09/63, 13/12/63, 13/03/64, 13/11/64, 13/08/65,

13/05/66, 13/01/67, 13/10/67, 13/09/68, 13/12/68, 13/06/69, 13/02/70, 13/03/70, 13/11/70,

13/08/71, 13/10/72, 13/04/73, 13/07/73, 13/09/74, 13/12/74, 13/06/75,

13/02/76, 13/08/76, 13/05/77, 13/01/78, 13/10/78, 13/04/79, 13/07/79, 13/06/80,

13/02/81, 13/03/81, 13/11/81, 13/08/82, 13/05/83, 13/01/84, 13/04/84, 13/07/84, 13/09/85, 13/12/85,

13/06/86, 13/02/87, 13/03/87, 13/11/87, 13/05/88, 13/01/89, 13/10/89, 13/04/90, 13/07/90,

13/09/91, 13/12/91, 13/03/92, 13/11/92, 13/08/93, 13/05/94, 13/01/95, 13/10/95,

13/09/96, 13/12/96, 13/06/97, 13/02/98, 13/03/98, 13/11/98, 13/08/99.