Final answer:
To find the implied interest rate for an investment that triples in 10 years, you use the compound interest formula. The correct calculation yields an annual interest rate of approximately 11.61%, making option (c) the correct answer.
Step-by-step explanation:
The implied rate of interest for an investment that triples your money in 10 years can be found by using the future value formula for compound interest, which is: FV = PV(1+r)^n. Here, FV is the future value of the investment, PV is the present value or the initial amount, r is the annual interest rate, and n is the number of years.
We know from the question that the future value is three times the present value (as the money will triple), and the time frame is 10 years. Thus, 3 = (1+r)^10. To solve for the interest rate, we take the 10th root of 3 and then subtract 1. This gives us (3^(1/10))-1 which approximately equals 0.1161 or 11.61% interest rate.
Therefore, the correct answer is c) 11.61% percent, since this is the rate at which the initial investment will have to grow each year to triple in 10 years.