Question

Alexis put $2000 in a savings account. After 4 years, she had $2543 in the account. What rate of interest did she earn? Use the formula A = Pert, where A is the ending amount, P is the principal (initial amount), r is the interest rate, and t is time.

Answer 1

Answer:

the other person is right, the answer is 6 %

Step-by-step explanation:

Answer 2

Alrighty

P=2000
A=2543
t=4

$A=Pe^{rt}$
$2543=2000e^{4r}$
solve

$2543=2000e^{4r}$

divide both sides by 2000

$\frac{2543}{2000}=e^{4r}$

take ln of both sides

$ln(\frac{2543}{2000})=ln(e^{4r})$

$ln(\frac{2543}{2000})=(4r)ln(e)$

$ln(\frac{2543}{2000})=(4r)(1)$

$ln(\frac{2543}{2000})=4r$

divide both sides by 4

$\frac{ln(\frac{2543}{2000})}{4}=r$

use your calculator

0.060049=r
convert to percent
that is about 6%

the interest rate is 6%