Pete can buy 4 cokes for $5 or 10 cokes for $12.50. How much will he would pay for 7 cokes?

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 have 17 cats that live in houses on your street, 24 dogs, 3 fish, and 4 hamsters. what percent of animals on your block are dogs?

How do i simply this expression (quadratic formula basis) on a ti-84 or normal calculator?