How much of temperature difference from ambient surroundings

Question

Problem

Owing to a faulty door contact, the small light bulb (25 W) inside a refrigerator is kept on and limited insulation lets 50 W of energy from the outside seep into the refrigerated space. How much of a temperature difference from the ambient surroundings at 20^oC must the refrigerator have in its heat exchanger with an area of 1 m² and an average heat transfer coefficient of 15 W/m² K to reject the leaks of energy?

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.