Question

Mrs. Wilkerson noticed that her in-laws’ birth dates have an unusual property. Her mother-in-law was born 5-31-36, and her father-in-law was born 9-25-34. Furthermore, her hus- band’s grandfather was born 7-7-14. How many birth dates in a century have this property, in which the sum of the month and the day equal the value of the last two digits of the birth year? Explain.