Puzzles
Lewis Carroll's chronology puzzle: how old is the lady, exactly?
In one of Lewis Carroll's puzzle stories, a lady is asked her age. She replies that eight years ago, her age was three times what her son's age would be six years from now, and her son's age now is exactly half of hers. How old is she now?
Reveal the answer
40 years old (her son is 20). Setting her current age as L and her son's as S: S = L/2, and L - 8 = 3(S + 6). Substituting gives L - 8 = 3(L/2 + 6), which solves to L = 40. Carroll published this as "Knot 1: Excelsior" in his 1885 puzzle collection A Tangled Tale, originally serialized in The Monthly Packet magazine as a set of story-puzzles for readers to solve by post.