Mike's grandmother opened a savings account in Mike's name and deposited some money into the account. The account pays an annual simple interest rate of 9%. After 12 years, the interest earned on the account was $8,640. How much money did Mike's grandmother deposit in the account? A.
$7,000
B.
$8,500
C.
$9,000
D.
$8,000

In this question we have to use the formula of simple interest, which is

I = P r t

Where I is the interest earned, P is the amount invested, r is the rate of interest and t is the time duration .

In the given question, I = $4840 , r =11% or 0.11, t=11, P is unknown .

Substituting the values in the formula, we will get

P=4000

So she invested $4000.

Step-by-step explanation:

answer: i'm not sure

step-by-step explanation: