posted by Lexi on .
Sam opened a money-market account that pays 2% simple interest. He started the account with $7,000 and made no further deposits. When he closed the account, he had earned $560 in interest. How long did he keep his account open?
7000*n*.02 = 560
n = 4 years
2% interest per year is $140 x 4 = $560
Terry invests $3,000, at 10% interest, compounded semiannually for 12 years. Use the compound interest formula to calculate the compound amount for his investment.