You ask your best friend to lend you $300 to buy your favourite toy. She says she can lend you the money only if you give her an extra $3 for every three months that pass before you return it. What is the total amount you must pay her if you return it after nine months?
Since its $3 extra per 3 months and 9 months pass it has to be an extra $9 for the $9 months.You already had to pay back the 300 so the equation would be (300+9=309)
