Given the following system of equations, what value of x makes the equations true? x+y= 3.25
x-y= 1.75

16 miles per gallon.

Step-by-step explanation:

On Monday Marci filled her car's tank and the odometer read 32,461.3 miles.

On Friday she filled the tank again and the odometer read 32,659.7 miles

It took 12.4 gallons to fill the tank

The distance covered by the car from Monday to Friday = 32,659.7 miles - 32,461.3 miles = 198.4 miles

The car depleted 12.4 gallons of fuel after travelling for the 198.4 miles

So one gallon would take Marci's car: miles

= 16 miles.