Question

Diana invested $3000 in a savings account for 3 years. She earned $450 in interest over that time period. What interest rate did she earn? Use the formula l-Prt to find your answer, where lis interest. Pis principal, ris rate and tis time. Enter your solution in decimal form rounded to the nearest hundredth. For example, if your solution is 12%, you would enter 0.12.

Answer 1

450 is your interest
3000 is your principle
3 is your time period

Our equation is:

450 = 3000(r)(3)

`(450)/(3000) = 3(r)`

`(.15)/(3) = r`
Interest rate = .05 or 5%

Answer 2

5%.

Explanation:

We have been given that Diana invested $3000 in a savings account for 3 years. She earned $450 in interest over that time period. We are asked to find the interest rate using the following formula.

`I=Prt`, where,

I = Amount of interest earned.

P = Principal amount,

r = Interest rate in decimal form,

t = Time in years.

Upon substituting our given values in above formula we will get,

`450=3000*r*3`

`450=9000*r`

Upon dividing both sides of our equation by 9000 we will get,

`(450)/(9000)=(9000*r)/(9000)`

`(1)/(20)=r`

`r=0.05`

Now let us multiply 0.05 by 100 to get our interest rate as percentage.

`r=0.05* 100\%`

`r=5\%`

Therefore, the interest rate is 5%.