Respuesta :

The annual interest rate is 0.06 or 6%.


thats the answer hope this helps

Answer:

6%

Step-by-step explanation:

Let's start by finding the amount earned per month:

[tex]\frac{18}{9}[/tex]=2

Now let's find the % per month

[tex]\frac{2}{400} =.005[/tex], or .5%

Now let's multiply by 12 months to get the annual interest rate

[tex].005 * 12 = .06[/tex] or 6%