Hi!
First I did 7,500 ÷ 100 which = 75. Then I did 75 x 6 which equals 450. 450 is what you get annually. Next you do 450 x 15 which equals 6,750 + 7,500. After 15 years you will get 14,250 total for 15 annual years combined. I'm only in 6th grade so I hope this is correct, if not I'm sorry. Let me know if you got it correct.