Question

Select the correct answer. Angela is driving across the state to her friend's house. She just filled her fuel tank to its maximum capacity of 26 gallons. If the amount of gas in her car decreases by 2 gallons every 48 miles, which of the following graphs best represents the number of gallons of fuel remaining?

Answer 1

Let L be the amount of gas Angela has at distance d. At d=0 she has 26, and we know that every 48 miles the gas decreases 2 gallons, so the rate of decrease of gas per mile is

`\frac{2\text{ }}{48}=(1)/(24)`

Then, the linear equation that models this problem is

`L=-(1)/(24)d+26`

(I used the minus sign since the amount decreases).

The gas will run out of gas whe she has driven

`\begin{gathered} 0=-(1)/(24)d+26 \\ (1)/(24)d=26 \\ d=624\text{ miles} \end{gathered}`

Then the graph that best fits the model is number Z. And the answer is D.