1.50*20=30 +10 for 1.55 off make it like paying 40 for 305 off
I suddenly couldn't make sense of the above. were you saying 30+10=40?
1.50*20 = $30 that's the money a buyer saves(@20 gallons, it should really have been 1.55) $10 is what buyer pays. you are adding savings and cost of the savings. what's your definition of the sum? Seemed like you are adding apples and oranges and comparing the sum with oranges.
1. $40 for 3.05 off is like paying $40 for getting $61 (@ 20 gallons) in return.
2. $20 for 1.55 off is like paying $20 for getting $31 (@ 20 gallons) in return.
3. $10 for 1.55 off is like paying $10 for getting $31 (@ 20 gallons) in return.
I don't see 1 and 3 are the same. I think 1. and 2 are the same (similar and 2 is actually better return)