Answer to Question #24864 in Calculus for Denis

Question

In a small Town it has been discovered that the relationship between the number of radius demanded varies linearly with its price. When the price per radio was $15, 1000 radious were demanded; when the price was 30$, 700 radious was demanded. a) Determine the price per radio when 500 radios were demanded? b) above what price will the demand be zero? I only know the answers, but I need someone to explain me. a) $40 b) $65
Please explain how did you come up with the answer.

Thanks a lot !!!