Question 894383
let a = his age at death
write an expression for each statement:
bobs youth lasted one sixth of his life.
{{{1/6}}}a 
he grew a beard after one twelfth more.
{{{1/12}}}a
 after one seventh more of his life,
{{{1/7}}}a
 he married. 5 years later he and his wife had a son. the son lived exactly one half as long as his father, and bob died four years after his son. how many years did bob live?
5 + {{{1/2}}}a + 4
:
Write an equation for all this
a = {{{1/6}}}a + {{{1/12}}}a + {{{1/7}}}a + 5 + {{{1/2}}}a + 4
multiply by 84 and cancel the denominators
84a = 14a + 7a + 12a + 420 + 42a + 336
Combine like terms
84a = 75a + 756
84a - 75a = 756
9a = 756
a = 756/9
a = 84 yrs old when he died