Question

The Rodriquez family drove 115 miles on 5 gallons of gasoline. Which of the following equations can be used to find how far they can travel on a full tank of 18 gallons. A. 5/115=18/x B. x/115=5/18 C. 115/5=18/x D. 5/115=x/18. PLZ HELP

Answer 1

if 5 gallons gets you 115 miles, you wanna ask yourself how many miles can one gallon get me. to do that you divide 115 miles / 5 gallons to get miles per gallon which is 23. so if 1 gallon gets you 23 miles, 18 gallons should be able to get you 18 x 23 miles which is 414 miles. This is the same thing as saying 115/5 = x/18 since thats exactly what we did! In your case, option A states this the other way around, but if you notice, the relationship is exactly the same! miles/gallon or gallon/miles as long as both sides of the equation are consistent with the units, the relationship is valid!