6. How long will it take for a $1,000 investment to double in size when invested at the rate of 8% per year? 7. How long will it take for a $3,000 investment to grow to $10,000 if invested at 5% interest a. compounded annually? b. compounded quarterly? 8. You borrow money on your credit card at 17.5% p.a., compounding quarterly. What is the effective annual interest rate? 9. The following interest rates are being offered by three competing banks: 4% compounded monthly; 4.1% compounded quarterly; 4.15% compounded annually. Which one is the most attractive