If a car can travel 105 miles on 7 gallons of gas,how far can it travel on 9 gallons of gas?

Question

This is a proportions problem.I think you have to cross multiply 

 

Answer 1

Your solution idea is correct. Thus 7 gallons per 105 miles is equivalent to 9 gallons per X miles. So the solution is 9 times 105 divided by 7, or 135 miles.