An ancient Greek was said to have lived 1/4 of his live as a boy, 1/5 as a youth, 1/3 as a man, and spent the last 13 years as an old man. How old was he when he died? Set up his life equation per time lived as a boy, youth, man, and old man 1/4 + 1/5 + 1/3 + x = 1. Using our LCM Calculator, we see the LCM of 3,4,5 is 60. This is our common denominator. So we have 15/60 + 12/60 + 20/60 + x/60 = 60/60 Combine like terms x + 47/60 = 60/60 Subtract 47/60 from each side: x/60 = 13/60 x = 13 out of the 60 possible years, so he was 60 when he died.