Margo borrows $400, agreeing to pay it back with 8% annual interest after 7 months. how much interest will she pay? round your answer to the nearest cent, if necessary.

Using the formula I=Pxrxt
P is the principal amount, $400.00.
r is the interest rate, 8% per month, or in decimal form, 8/100=0.08.
t is the time involved, 7month(s) time periods.
Since your interest rate is "per month" and you gave your time interval in "month(s)" we need to convert your time interval into "month" as well.
So, t is 7month time periods.
To find the simple interest, we multiply 400 × 0.08 × 7 to get thThe interest is: $224.00