Final answer:
To travel 100 miles, at least 5 gallons of gas are needed.
Step-by-step explanation:
To find out how many gallons of gas are needed to travel 100 miles, we can set up an inequality. Letting g be the gallons of gas, we know that the car can travel 20 miles on one gallon. So the inequality would be: 20g ≥ 100.
To solve for g, we divide both sides of the inequality by 20: g ≥ 5.
Therefore, at least 5 gallons of gas are needed to travel 100 miles.
Learn more about Gallons of gas needed to travel a given distance