The Randolphs used 12 more gal of fuel oil in October

than in September and twice as much oil in November as in September. If they
used 132 gal for the 3 months, how much was used during each month?

Let x = the gallons of fuel oil used in September, and solve this equation.

x + (x + 12) + 2x = 132

To solve the equation, combine like terms:

4x + 12 = 132

Next, isolate the term with the variable:

4x = 132 - 12

Simplify:

4x = 120

Now, divide both sides by 4 to solve for x:

x = 120 / 4

x = 30

Therefore, the Randolphs used 30 gallons of fuel oil in September.

To find the amount used in October, add 12 gallons to this:

October = 30 + 12 = 42 gallons

To find the amount used in November, multiply the amount used in September by 2:

November = 30 * 2 = 60 gallons

Therefore, the Randolphs used 30 gallons of fuel oil in September, 42 gallons in October, and 60 gallons in November.