A radio commercial for a loan company states; "You only pay 26 cents a day for each $500 borrowed." If you borrow $1,289 for 223 days, what amount will you repay, and what annual interest rate is the company actually charging?
Assume a 360 day year, round to two decimal places.
The interest amount ($0.26), $500 principal, and time (1 day of a 360-day year), are enough to calculate required interest rate.
Being short-term SIMPLE INTEREST, we get:
Interest rate, or