The correct interpretation of the inequality \( g \leq 6 \), in the context of the real-world problem of buying gas with $20, is:
You can buy from 0 to 6 gallons of gas with $20.
This means that you can buy any amount of gas up to a maximum of 6 gallons. The gas cannot be negative, so the practical range is from 0 gallons (no purchase) up to 6 gallons, depending on the price per gallon.