Answer:
B. 7.4 gal
Step-by-step explanation:
Let x represent the number of gallons of gas needed to complete the trip.
Given that Zara drove 168 miles on 8 gallons of gas, if she had 155 miles left to complete her trip, we can go ahead and determine x by setting up proportions as shown below;
![\frac{168\text{ miles}}{8\text{ gallons}}=\frac{155\text{ miles}}{x\text{ gallons}}](https://img.qammunity.org/2023/formulas/mathematics/college/nmvau5k2gjqhw8c6sjx14aon2w5j6empj3.png)
If we cross multiply, we'll have;
![\begin{gathered} 168x=155*8 \\ 168x=1240 \end{gathered}](https://img.qammunity.org/2023/formulas/mathematics/college/q8v5xzbhe2r2cj0qaiyaglbg8em4gkaoma.png)
Let's now divide both sides of the equation by 168;
![\begin{gathered} (168x)/(168)=(1240)/(168) \\ x=7.4\text{ gal} \end{gathered}](https://img.qammunity.org/2023/formulas/mathematics/college/blwzsseg7dyli5apvgrjxud98xbe6sao27.png)
Therefore, Zara would need 7.4 gallons of gas to complete her trip.