The equations is A= P(1 + r)^t, where P is the amount invested, r is the interest rate, and t is the time. So A, your total amount in the bank account including interest, is equal to 6500(1.04)^7, which is The answer is $8553.56 (that's what I rounded to). That is your total, so subtract 6500 from that number and you'll get the interest amount.