Pls help me 19 and 20

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 value of n in the equation -1/2(2n+4)+6=-9+4(2n+1)

Aramp rises 4 feet over a distance of 10 feet. what is the length of the ramp?