Okay so on average if they can go 25 miles per gallon that would mean you could just multiply 25 and 7 to get 175. So on average they could go 175 miles on 7 gallons of gas. Keep in mind that the answer can and will change depending on traffic, how fast or slow they are going, and if they are traveling behind a big-rig that moves more air that would normally be putting pressure on the car to push out of the way but the big-rig helps save gas but it can also waste more gas if they are driving slower then normal. Sorry for the extra information once I start it's hard to stop. Any way I hope this helps.
We must remember that range of function corresponds to the set of values of in the graph (+y direction). Given that is a stretched version of , the range of corresponds to the range of multiplied by 4. Then,