[dba-Tech] OT: Friday brain-teaser

On 11 Jan 2013 at 16:04, Arthur Fuller wrote:

> This is a very old problem concerning an ancient Greek whose name I won't
> mention, since that might enable you to simply Google and obtain the answer.
> 
> His boyhood last 1/6th of his life; his beard grew after 1/12th more; he
> married after 1/7th more, and his son was born five years later. The son
> lived to half his father's age, and the father died four years after his
> son. How old was the father?
> 
> -- 
> Arthur
> 

If I haven't made any mistakes:

x = fathers lifespan
sb = son's birth year
sd = sons death year

First sentence: 
1. sb = (x/6 + x/12 + x/7 + 5)
Second Sentence: 
2a. sd = sb + x/2
2b. sd = x- 4

so x- 4 = sb + x/2
so sb = x - 4 - x/2

Combining 1 and 2

x/6 + x/12 + x/7 + 5
= x - 4 - x/2

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

LCD = 84 so

84x/84 - 42x/84 - 14x/84 - 12x/84 - 7x/84 = 9

(84-42-14-12-7)x/84 = 9

9x/84 = 9

x/84 = 1

x = 84