Help on this would be much appreciated thanks

12x + 1 = 25 solve the following equation. then place the correct number in the box provided.

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 percent of 18 is 24? and plz explain thx.