6. Riley let his friend borrow $12,750. He wants to be paid back in 4 years and is going to charge his friend a 5.5% interest rate. a. How much money in interest will Riley earn? b. When Riley's friend pays him back, how much money will he have gotten paid back in all?

Johnny rode his bike to a friends house 4 blocks down the street in his neighborhood. he immediately rode back home once he realized his friend was unable to play. what was his displacement for the total bike ride trip? what could you use as a reference point ? show the steps to solve this problem.