Question
Stefan invests 7,690 in a retirement account with a fixed annual interest rate of 9% compounded continuously.How long will it take for the account balance to reach 38,858.26 18 years 17 years 15 years 16 years
Solution
4.2
(339 Votos)
Felipe
Profissional · Tutor por 6 anos
Resposta
To solve this problem, we can use the formula for continuous compounding interest:
Where:-
is the final amount-
is the principal amount (initial investment)-
is the annual interest rate (as a decimal)-
is the time in years-
is the base of the natural logarithmGiven:-
-
(since 9% as a decimal is 0.09)We need to find
.First, plug in the given values into the formula:
Next, solve for
:1. Divide both sides by 7,690:
2. Take the natural logarithm (ln) of both sides to solve for
:
3. Calculate \( \ln(5.05) \):
4. Solve for
:
So, it will take approximately 18 years for the account balance to reach \$38,858.26.Therefore, the correct answer is: