Paul has a part time job selling computers at a local electronics store. He earns a fixed hourly wage, but can earn a bonus by
selling warranties for the computers he sells. He works 20
hours per week. In his first week, he sold eight warranties and
earned $220. In his second week, he managed to sell.13
warranties and earned $280. What is Paul's hourly rate, and
how much extra does he get for selling each warranty?