Please Help! I will give you a lot of points if you do! -You can't use our regular number system to solve this problem. You have to use Hindu-Arabic number system

Can someone check if i did this correct. it’s number 4 if you’re wondering.

Ricky takes out a $31,800 student loan to pay his expenses while he is in college. after graduation, he will begin making payments of $190.66 per month for the next 30 years to pay off the loan. how much more will ricky end up paying for the loan than the original value of $31,800? ricky will end up paying $ more than he borrowed to pay off the loan.

What is the rate for one gallon of gasoline