For any given date (such as April 20), one out of every seven years it will fall on any given day of the week - at least, that's what happens in the long-term average.
20th April 1948 was a Tuesday.
April 20 1948 was a Tuesday.
April 20 1999 was a Tuesday.
April 20 2010 was a Tuesday.
April 20, 1954 fell on a Tuesday.
Tuesday.
tuesday
It was a Tuesday.
Tuesday
Tuesday.
2004 & 2010
It was a Tuesday.