Pebble lived 1/12 of his life as a small child and 1/6 more as a “youth”. Then he married Bloomie and lived happily 1/7 of his life plus 5 more years. Then they had a son, Nelius, whom, sadly, Pebble outlived by four years. Nelius lived to be 1/2 of Pebble’s final age. How old was Pebble when he died?

Pebble lived *x* years; his son lived *x*/2 years.

So *x*/12 + *x*/6 + *x*/7 + 5 + *x*/2 + 4 = *x*

This leads to 75*x*/84 + 9 = *x*, which leads to *x* = 84.