beth put $8,000 in a savings account. at the end of a year the account had earned $720 in interest. what was…

beth put $8,000 in a savings account. at the end of a year the account had earned $720 in interest. what was the yearly interest rate on the account? a 18.5% b 17.5% c 10.0% d 9.0%

beth put $8,000 in a savings account. at the end of a year the account had earned $720 in interest. what was the yearly interest rate on the account? a 18.5% b 17.5% c 10.0% d 9.0%

Answer

Explanation:

Step1: Recall interest - rate formula

The formula for simple - interest is $I = Prt$, where $I$ is the interest, $P$ is the principal amount, $r$ is the interest rate, and $t$ is the time in years. In this case, $t = 1$ year, $P=$8000$, and $I = $720$. We need to solve for $r$. Since $t = 1$, the formula simplifies to $I=Pr$.

Step2: Rearrange the formula to solve for $r$

We can rewrite the formula $I = Pr$ as $r=\frac{I}{P}$. Substitute $I = 720$ and $P = 8000$ into the formula: $r=\frac{720}{8000}$.

Step3: Calculate the interest rate

$\frac{720}{8000}=0.09$. To convert a decimal to a percentage, we multiply by 100. So $r = 0.09\times100%=9.0%$.

Answer:

D. 9.0%