Answer: Ian would have drove 91 miles using only 3 gallons of gas.
Step-by-step explanation: I used paper and pencil and used a T-chart putting one section at the top “gallons” and the other “miles”; under gallons I put 7 because the question stated with “7 gallons of gas”; under miles I put 217 because the question states that with 7 gallons of gas Ian’s car travels 217 miles so using the T-chart I want to simply the 7 gallons of gas to one gallon of gas to figure out how miles Ian’s car would go only using 3 gallons of gas; by dividing 7 by 7 giving me 1, and with a T-chart you wanna do the same thing to both sides meaning I divided 217 by 7 as well giving me 31 for 1 gallon of gas, meaning Ian’s car would travel 31 miles with only using 1 gallon of gas. After I find that answer I go to multiply the 1 under “gallons” by 3 to and again, if you do it to one side you have to do it to the other meaning I multiplied 31 my 3 as well; giving me 91. Meaning with only using 3 gallons of gas Ian’s car would travel 91 miles!