Question

Compound interest ?

Answer 1

My answer may not be correct but I feel pretty confident. The answer is $549.08

Answer 2

Compound interest is when interest grows every year. Say you owe the bank $1,000. The interest rate is 10%. After a year, you owe $1,100. Why? You still haven't paid this year's interest. So for the second year, you need to pay 10% of $1,100 in interest. This is used a lot in real life. There's also simple interest, where interest remains the "same". You pay 10% for $1,000 every year, and not of $1,100, $1,210, and so on. 
I know you already have the answer, so I hope this provides insight on how to solve problems in the future :)