Consider yourself as an entrepreneur at the mall selling 6000 donuts a day at 50¢ each.
When you raised the price to 70¢ each, the sale dropped to 5000 donuts per day. Assume that
there is a linear relationship between the price and number of donuts sold. Further assume that
there is a fix cost (overhead) of $1000 per day and the cost of each donut is 25¢. What would be
the price of the donut to maximize the profit?