Dave, a retired Refuse Technician and part time Mathematician is dead. Poor Dave.
The moment before he died he wrote down the facts of his life, they are as follows.
He considered himself a child for exactly 1/6 of his life, he was elated to have managed to grow his first beard after a further 1/12th of his life. A further 1/7th of his life later he married his ugly wife Martha. Five full years later they had their only child, an irksome little git called Barry, fortunately Barry wasn’t long for this world and died 4 years before his father. At his time of death Barry’s age was exactly half the age that his father would live to see.
How old was Dave?