Simple interest is given by the formula a = p + p r t a = p + p r t . where a a is the balance of the account after t t years, and p p is the starting principal invested at an annual percentage rate of r r , expressed as a decimal. dustin is investing money into a savings account that pays 5% simple interest, and plans to leave it there for 10 years. determine what dustin needs to deposit now in order to have a balance of $20,000 in his savings account after 10 years. dustin will have to invest $ now in order to have a balance of $20,000 in his savings account after 10 years. round your answer to the nearest dollar.