The Randolph’s used 12 more gal of fuel oil in October

Question

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?

I can solve the problem but I need to figure out the order of the expression. Can anyone help?

Answer 1

oct-12=sep
Nov=2sep

sep+oct+nov=132

Then substitute..
Oct-12 + Oct + 2sep=132
Oct-12 + Oct + 2(Oct-12)=132

enough?