Let x represent the number of gallons of gas required to drive 1 mile
From the information given, Kerry drove 312 miles on 11 gallons of gas. Thus, we can set up the following equations
312 miles = 11 gallons
1 mile = x gallons
By crossmultiplying, we jave
312 * x = 1 * 11
312x = 11
Dividing both sides of the equation by 312,
x = 11/312
This means that 11/312 gallons is required to drive 1 mile
She had 175 miles left to complete her trip. This means that the number of gallons needed to complete 175 miles would be
175 * 11/312
= 6.1699
By approximating to 1 decemal place,
the number of gallons needed is 6.2 gal