Question

a freezer can change the internal temperature of a steak by -2.4°f every 8 minutes. which expression represents how much the freezer can change the temperature of the steak in 3\frac{3}{4} hours? a -2.4 × (3\frac{3}{4} ÷ 8) b -2.4 × (3\frac{3}{4} × 8 ÷ 60) c -2.4 × (3\frac{3}{4} ÷ 8 ÷ 60) d -2.4 × (3\frac{3}{4} × 60 ÷ 8)

Explanation:

Step1: Convert hours to minutes

Since \(1\) hour \( = 60\) minutes, then \(3\frac{3}{4}\) hours \(=\frac{15}{4}\times60\) minutes.

Step2: Calculate the number of 8 - minute intervals

The number of 8 - minute intervals in \(3\frac{3}{4}\) hours is \(\frac{15}{4}\times60\div8\).

Step3: Find the temperature change

The temperature change per 8 - minute interval is \(- 2.4^{\circ}F\). So the total temperature change is \(-2.4\times(\frac{15}{4}\times60\div8)\) (which is equivalent to \(-2.4\times(3\frac{3}{4}\times60\div8)\)).

Answer:

D. \(-2.4\times(3\frac{3}{4}\times60\div8)\)