Question 27432
The wording of the problem is not totally clear.  For instance, "After a twelfth more, ...."  Does that refer to 1/12 of his total life or some other number?  Anyway, I will give it a try.


1/6x + 1/12x + 1/7x + 5 + 4 = 1/2x
Multiply each term by a common denominator, in this case 84.
14x + 7x + 12x + 420 + 336 = 42x
Combine like terms.
420 + 336 = -14x - 7x -12x + 42x
756 = 42x
18 = x 


Did I do something wrong?  The answer doesn't seem logical.