SOLUTION: If $7,000 is placed in an account with an annual interest rate of 4%, how long will it take the amount to quadruple if the interest is compounded annually? Round your answer to two

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Question 728803: If $7,000 is placed in an account with an annual interest rate of 4%, how long will it take the amount to quadruple if the interest is compounded annually? Round your answer to two decimal places.

Answer by solver91311(24713)   (Show Source): You can put this solution on YOUR website!




Where is the future value, is the present value, i.e. the starting principal, is the interest rate as a decimal (the percentage divided by 100), is the number of compounding periods per year, and is the number of years. Since you are compounding annually, and the formula reduces to:



Since you want the principal to quadruple, must be true, hence solve:



for

Hint: Take the log of both sides, any base -- it doesn't matter. Then use:

John

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