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?  Choose the correct choice
A) $ 3,750 B) $ 5,600 C) $ 8,100 D) $ 15,000 E) $ 31,500

Rationale: "x = 8 % 112 / x years = 112 / 8 = 14 years now , money triples every 14 years therefore , in 14 yrs , if $ 3500 triples to $ 10500 , in 28 years , it will again triple to $ 10500 * 3 = $ 31,500 answer e"
Answer: E