Compound Interest and the Rule of 72

Explain, in your own words the concept of 'compound interest' and 'the rule of 72'. Use examples. Also using the Compound Interest Calculator - find out how much money you would have if you saved $1 per day ($365 per year) from age 18 to 65 (retirement age). Use 8% interest in your calculation; which is about how much the overall US stock market goes up each year.