Business Joaquin and Marva are selling lemonade. The higher the price they charge for a cup of lemonade, the fewer cups they sell. They have found that when they charge p cents for a cup of lemonade, they sell 100 2p cups in a day.
a. Find a formula for the function r(p) that gives their total daily revenue.
b. Find the price that Joaquin and Marva should charge to generate the highest possible revenue.