11. 300=12x (X being the number of gallons per miles)
12. It will take 30 gallons of gas to travel 750 miles (first divide 300 by 12, which gives you 25 miles per gallon. Then divide 750 by 25, which gives you 30 gallons to travel 750 miles)
13. It'll cost a total of $112.5 for gas to go on your trip. (Multiply 30(gallons)×3.75(cost of 1 gallon)= 112.5(total cost of gas)