A Child is Full of ...
Problem
My cousin was 24 years old on Friday April 5th in 1974.
On what day of the week was she born?
Student Solutions
Andrew of Farlingaye High School, Katherine and Claire (from where?) and Sarah, Richard, Jack, Jan, Chris and Micheal all of Necton Middle School and Alison of Wymondham High School agreed that it is Wednesday's child which as we know is full of WOE.
Soon Xing from Singapore explained it as follows:
On every leap year there is an extra day. Every year, the day of the week increases by one day, but at a leap year the day of the week increases by two days. The leap years from 1950 to 1974 were 1952, 1956, 1960, 1964, 1968 and 1972.
At this point Soon Xing gave a complicated formula. All that is needed is to say that the day of the week must have increased by 30 days (1 day for each of the 24 years, plus 1 day for each of the 6 leap years). Now 30 days is 4 weeks and 2 days so the day of the week has increased by 2 days which means that she was born on a Wednesday.