Public health information can be broadcast at a cost of $100. Public health information is a pure public good, in that many people can use the information simultaneously and preventing people from using the information is very difficult. One group of residents has a demand curves for public health information of the form Q = 50 - P. Here Q is the number of public health broadcasts per month and P is the price per broadcast. Another group has a demand curve of Q = 140 - P.