You can put this solution on YOUR website!
Ok to solve this, we first have to set up our variables.
Let n= The amount of oil used in September
Let n+12= Amount of Oil used in October
Let 2n= Amount of oil used in November
So now we have to add everything up and have it total 132 gallons of gas, because that's how much they used.
Now we combine like terms, and solve for n.
Ok so we now know that n=30, now we can plug thirty for n and figure out how much oil they used for each month.