Publishing—Magazine Publications: By inspecting their tracking records, the telemarketing...

Publishing—Magazine Publications: By inspecting their tracking records, the telemarketing company Calls-R-Us has concluded that the monthly profit from selling magazine subscriptions can be modeled by

where x represents the number of subscriptions sold per month, and P(x) represents profit in dollars. Determine MP, the marginal profit function. Evaluate MP(55) and interpret.