he spent 1/6 of his life as a child, 1/12 as an adolescent, and 1/7 as a bachelor.
5 years after he's married, he has a son.
son dies 4 years before his father at half his father's final age.
how long did he live?
if we add up 1/6 and 1/12 and 1/7, we get 33/84.
this should mean that he dies at 84 and has 51 years left to live.
if that holds up, then we found the answer.
let's see if it does.
assuming we're right, then he gets married at 33 years of age.
5 years later he has a son when he is 38 years old.
based on our assumption, he dies at 84.
his son has died 4 years earlier at half his age when he dies which means his son has died at age 42.
here's the timeline.
his age his son's age description of event
38 0 his son is born.
80 42 his son dies.
84 he dies.
when his son dies at 42, he is 80 (80 - 38 = 42)
4 years later he dies at 84.
numbers appear to check out so the solution is good.
it appears the only information we needed was to be able to add up 1/6 + 1/12 and 1/7 to find out how much of his life was consumed when he got married.
the remainder from the denominator is what he had left.
the denominator is how long he lived.