Properties of Identity, Inverses, and Zero · Exercise 54

Cooking time Helen bought a $\text{24}-\text{pound}$ turkey for her family’s Thanksgiving dinner and wants to know what time to put the turkey in the oven. She wants to allow $20$ minutes per pound cooking time.

ⓐ Calculate the length of time needed to roast the turkey by multiplying $24\cdot 20$ to find the number of minutes and then multiplying the product by $\frac{1}{60}$ to convert minutes into hours.
ⓑ Multiply $24\left(20\cdot \frac{1}{60}\right).$
ⓒ Which of the Properties of Real Numbers allows you to multiply $24\left(20\cdot \frac{1}{60}\right)$ instead of $\left(24\cdot 20\right)\frac{1}{60}?$

OpenStax, Prealgebra 2e · §7.4 Properties of Identity, Inverses, and Zero · Exercise 54