A friend of yours is considering three cell phone service providers. Provider A charges $120 per month for the
service regardless of the number of phone calls made. Provider B does not have a fixed service fee but instead charges $1 per minute for calls. Provider C charges $30 per month and $0.5 per minute for calls. Your friend's monthly demand for minutes of calling is given by the equation QD = 150 - 50P, where P is the price of a minute.
1. Under provider A, the cost of an extra minute on the phone is $0. Under provider B, the cost of an extra minute on the... View the full answer