Mahesh borrowed $6,480 from Becky. He signed a contract agreeing to pay it back 9 months later with 4.15% simple interest. After 5 months, Becky sold the contract to Stan at a price that would earn Stan 5.00% simple interest per annum. Calculate the simple interest rate that Becky earned during the period that she held the contract. Express your answer as a percentage rate rounded to 2 decimal places but don't include the % sign