Jeremy opened two savings accounts at the beginning of 2010, each with an initial deposit of
$4,000. He deposited $500 into each account at the beginning of 2011 and 2012. Both
accounts had an interest rate of 3.15%. Account A earned simple interest, and account B
earned interest that was compounded annually. By the end of 2012, which account earned
more interest, and how much more interest did it earn?