after 3 years, $8,000 deposited in a savings account with simple interest had grown to a total of $9,680…

after 3 years, $8,000 deposited in a savings account with simple interest had grown to a total of $9,680. what was the interest rate? use the formula i = prt, where i is the interest earned, p is the principal (starting amount), r is the interest rate expressed as a decimal, and t is the time in years.

after 3 years, $8,000 deposited in a savings account with simple interest had grown to a total of $9,680. what was the interest rate? use the formula i = prt, where i is the interest earned, p is the principal (starting amount), r is the interest rate expressed as a decimal, and t is the time in years.

Answer

Explanation:

Step1: Calculate the interest earned

The interest $i$ is the total amount minus the principal. So $i=9680 - 8000=1680$.

Step2: Rearrange the simple - interest formula for $r$

Given $i = prt$, we can solve for $r$. Divide both sides of the equation by $pt$ to get $r=\frac{i}{pt}$.

Step3: Substitute the known values

We know that $p = 8000$, $t = 3$, and $i = 1680$. Substituting these values into the formula for $r$, we have $r=\frac{1680}{8000\times3}$. First, calculate $8000\times3 = 24000$. Then $r=\frac{1680}{24000}=0.07$.

Step4: Convert $r$ to a percentage

To convert a decimal to a percentage, multiply by 100. So $r = 0.07\times100 = 7%$.

Answer:

7%