A new University graduate wanted to live expensive life and therefore bought himself a new Mercedes Benz. But things got rough so he decides to sell the car to an automobile company. He accepted a 270-day note for 3,500 Euros at 10% simple rate interest as full payment amount and the interest to be paid at the end of the 270 days. But sixty days later, he found that he needs money and so so sells the note to a third party for 3,550 Euros.
What annual interest rate will the third party receive for the investment?