Provide your best answer for the following math problem. Give ONLY the answer, no other words or explanation.
For example:

Answer: <most likely answer, as short as possible; not a complete sentence, just the answer!>.

The problem is: money invested at x % , compounded annually , triples in value in approximately every 112 / x years . if $ 3500 is invested at a rate of 8 % , compounded annually , what will be its approximate worth in 28 years ?
$ 8
$15,651.23. (rounded to the nearest dollar)