Verified Answer :

To answer the question, use the concept of ratio and proportion. Haley's given mileage should be equal all throughout. Let x be the minimum number of gallons that Haley needs, the proportion becomes,
                                18 miles / 1 gallon = 200 miles / x gallons
The value of x is 11.11 gallons. Thus, Haley need at least 11.11 gallons.

Answer:

\(11\ gallons\)

Step-by-step explanation:

we know that

Haley's car gets at least \(18\) miles per gallon

so

by proportion

Find the minimum number of gallons she'll need for a trip that is \(200\) miles

\(\frac{1}{18}\frac{gallon}{miles} =\frac{x}{200}\frac{gallon}{miles}\\ \\x=200/18\\ \\x= 11.11\ gallons\)