The Randolph’s 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 3 months, how much was used during each month?

Let the usage in the three months be S, O and N.
O = S + 12
N = 2S
S+O+N = S + S + 12 + 2S= 132
3S = 120
Solve for S.
The use the O and N equations to get the others.

To solve this problem, we can set up a system of equations using the given information. Let's denote the usage in September, October, and November as S, O, and N respectively.

According to the problem, the usage in October is 12 gallons more than in September, so we can write O = S + 12.

Similarly, the usage in November is twice the usage in September, so we can write N = 2S.

We also know that the total usage for the three months is 132 gallons, so we can write the equation: S + O + N = 132.

Substituting the expressions for O and N, we have:

S + (S + 12) + 2S = 132.

Combining like terms, we get:

4S + 12 = 132.

Subtracting 12 from both sides, we have:

4S = 120.

Dividing both sides by 4, we find that S = 30.

Now, we can substitute S = 30 back into the equations for O and N to find the values for October and November:

O = S + 12 = 30 + 12 = 42.
N = 2S = 2(30) = 60.

Therefore, the usage for each month is as follows:
September: 30 gallons.
October: 42 gallons.
November: 60 gallons.