What is the percent decrease from $80 to$64 rounded to the nearest percent

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.

You eat $0.85 for every cup of hot chocolate you sell. how many cups do you need to sell to earn $55.25

16x^2-16x=5 solve the equation by completing the square