So this person was complaining how his beloved 89 octane now costs $4.739 at the Wawa vs $4.299 for regular. He further lamented the spread in price between 89 and 93 octane was $.16 ($4.899 per gallon), but $.44 between 87 and 89.

I said "put two thirds 87 in your tank and one third 93 and you have 89 octane for a cheaper price." He looked puzzled, but we did the math for 3 gallons. (4.299+4.299+4.899) is $13.49 4.739*3 is $14.21. Under this scenario, he is saving $.72 on 3 gallons or $.24 on one gallon.

He was elated. I'm in NJ and everything is full serve here. He did 2 separate transactions. One for 8 gallons of 87 and a separate transaction for 4 gallons of 93. He said the gas attendant wasn't overly happy. He's now telling everyone the story how he beat the system.