Chapter 4.1, Problem 54PFA

To determine

To find the equation that represents the given situation.

Answer to Problem 54PFA

  $y=-6x+70$ & option D is correct.

Explanation of Solution

Given:

At 6.00 P.M, the temperature is ${70}^{\circ }\text{F}$ and the temperature will drop $6^{\circ }\text{F}$ each hour.

Calculation:

Let y be the temperature in degrees Fahrenheit and x be the number of hours.

Then the dropped temperature after x hours is $6x^{\circ }\text{F}$ .

Therefore the equation is,

  $\begin{array}{l}y=\text{Temperature}\text{at}\text{6}\text{.00}\text{P}\text{.M}-\text{dropped}\text{temperature}\text{after}x\text{hours}\\ =70-6x\\ \therefore y=-6x+70\end{array}$

Hence option D is correct.