You need to prepare a turkey dinner for a big party. You are expecting a lot of guests so you bought a 13 kg turkey. Because you have no prior experience in cooking such a big turkey so you called your mom. Unfortunately, your mom also has never cooked such a big turkey. However, she told you that every Thanksgiving, she buys a 7 kg turkey for the family and it takes about 2.5 hour to cool.

Assuming that cooking a turkey is a diffusion process and that the density and diffusion coefficients are the same for all sizes of turkeys. Please tell me about how long will it takes for you to cook 13kg turkey?