At an interest rate of 10% per year, the equivalent amount of $10,000 one year ago is closest to: ( (A) $8264 (B)$9091 (C) $11,000 ) (D)$12,000 Assume that you and your best friend each have $1000 to invest. You invest your money in a fund that pays 10% per year compound interest. You friend invests her money at a bank that pays 10% per year simple interest. At the end of 1 year, the difference in the total amount for each of you is: ( ) (A) You have $10 more than she does (B) You have $100 more than she does (C) You both have the same amount of money (D) She has $10 more than you do The time it would take for a given sum of money to double at 4% per year simple interest is closest to: ( ) (A) 30 years (B)25 years (C) 20 years (D)10 years