Samantha invested $670 in an account paying an interest rate of 5.5% compounded daily. Assuming no deposits or withdrawals are made, how long would it take, to the nearest year, for the value of the account to reach $1,740?

Respuesta :

Answer:

  17 years

Step-by-step explanation:

The formula for the value of an account earning compound interest can be used to find the number of years. That formula is ...

  A = P(1 +r/n)^(nt)

where P is the principal invested at annual rate r compounded n times per year for t years.

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Solving for t, we find ...

  A/P = (1 +r/n)^(nt) . . . . . . divide by P

  log(A/P) = nt·log(1 +r/n) . . . . take logarithms

  t = log(A/P)/(n·log(1 +r/n)) . . . . . divide by the coefficient of t

For the given values, the time required is ...

  t = log(1740/670)/(365·log(1 +0.055/365)) ≈ 17.353

It would take about 17 years for the account value to reach $1740.

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Additional comment

The time-value-of-money (TVM) apps of your calculator or spreadsheet can be used to find the time period of interest. Here, setting P/Y = 1 gives N in years.

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