mathematical riddle using equation?

  • Thread starter Thread starter Sianadh
  • Start date Start date
S

Sianadh

Guest
can anyone answer this, with showing all of your working out. you must find out how old the man was when he died, using an equation

Riddle: his boyhood lasted one-sixth of his life; he married after one-seventh more; his beard grew after one-twelth more, and his son was born 5 years later; the son lived to half his father's age, and the father died 4 years after the son.
 
1/6x + 1/7x + 1/12x + 5 + 4 = 1/2x
(1/6+1/7+1/12)x +9 = 1/2x common denominator=84
(14/84+12/84+7/84))x + 9 = 1/2x add & multiple both sides by 2
2(33/84)x + 18 = x
33/42x + 18 = x subtract 33/42x from both sided
18 = 9/42x mult by 42/9
84 = x = father's age
 
Back
Top