Enigma 277: Professor Calendar’s sons
From New Scientist #1424, 4th October 1984 [link]
Professor Calendar (1930-82) was a noted mathematician. The almanacs published by him were well known. A census enumerator once asked him about the ages of his sons. The professor said: “All my three sons have the same date of birth and were born on the same day of the week”. He continued, “there are no twins and the date of today is the sum of their ages”. The enumerator, an able mathematician himself, replied: “Sir, I could not get their ages. Is one of them twice as old as his brother?”. The professor replied in the affirmative.
What was the age of the eldest son?