Answer:
9%
Step-by-step explanation:
To solve this problem we can use a modified version of the simple interest formula which is shown below:
[tex]r=\frac{I}{Pt}[/tex]
I = interest amount
P = principal amount
t = time (in years)
To start, we need to convert 1 month into a decimal (out of a year):
[tex]\frac{1}{12}=0.0833[/tex]
Now we can plug in the values:
[tex]r=\frac{81}{(10,800)(0.0833)}[/tex]
[tex]r=0.09[/tex]
The last step is to convert 0.09 into a percent:
0.09(100) = 9
The annual interest rate is 9%
