A friend of yours is considering two cell phone service providers. Provider A charges $110 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. Your friend's monthly demand for minutes of calling is given by the equation QD=100-20P, where P is the price of a minute.

With Provider A, the cost of an extra minute is $____ . With Provider B, the cost of an extra minute is $____ .

Given your friend's demand for minutes and the cost of an extra minute with each provider, if your friend used Provider A, he would talk for ________ minutes, and if he used Provider B, he would talk for ________ minutes. This means your friend would pay $_____ for service with Provider A and $______ for service with Provider B.

Your friend would obtain $______ in consumer surplus with Provider A and $______ in consumer surplus with Provider B.

Given this information, which provider would you recommend that your friend choose?

Provider A

Provider B