Problem
Someone is booking a meal in a restaurant for a group of people. They are told that there is a set menu that costs £9.50 per adult and £5 per child, and there is also a fixed charge of £1 per head for each meal served. Derive an expression for the total cost of the meal, in pounds, if there are x adults and y children.
The response should include a reference list. Double-space, using Times New Roman 12 pnt font, one-inch margins, and APA style of writing and citations.