Chapter 1.9, Problem 818E

Cooking time Helen bought a 24-pound turkey for her family’s Thanksgiving dinner and wants to know what time to put the turkey In to the oven. She wants to allow 20 minutes per pound cooking time. Calculate the length of time needed to roast the turkey:
(a) First, by multiplying $24·20$ to find the total number of minutes and then multiplying the answer by $\frac{1}{60}$ to convert minutes into hours.

(b) Next, by multiplying $24\left(20·\frac{1}{60}\right)$ .

(c) Which of the properties of real numbers says that your answers to parts (a), where you multiplied $\left(24·24\right)\frac{1}{60}$ , and (b), where you multiplied $24\left(20·\frac{1}{60}\right)$ should be equal?