Problem Solving

If money is invested at r percent interest, compounded annually, the amount of the investment will double in approximately 70/r years. If Pat's parents invested $5,000 in a long-term bond that pays 8 percent interest, compounded annually, what will be the approximate total amount of the investment 18 years later, when Pat is ready for college?
(A) $20,000
(B) $15,000
(C) $12,000
(D) $10,000
(E) $9,000




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