To find the amount of miles, we can begin by identifying the unit rate through division:
120 miles / 5 gallons = 24 miles for each gallon
Using this unit rate, we can multiply by 12 to find the amount of miles that can be driven with 12 gallons:
12 gallons • 24 miles per gallon = 288 miles
With 12 gallons of gas, Tanisha can drive 288 miles at most.