A local coffee shop charges $4 for a cup of coffee and sell 30 cups per day. They determine that every time they decrease the price of a cup by $0.20 they sell 3 more cups of coffee
per day. What should they charge for a cup of coffee to maximize their profits?

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.