Your grandfather started his own business 52 years ago. He opened an investment account at the end of his third month of business and contributed $x. Every three months since then, he faithfully saved another $x. His savings account has earned an average rate of 5.73 percent annually. Today, his account is valued at $289,209.11. How much did your grandfather save every three months assuming he saved the same amount each time? $328.67 $284.02 $262.25 $331.09 $226.78