Gas price matching amount

[B M]

Ok so my brother-in-law, said he does this all the time. He pumps one gallon of gas then verifies the actual price to the amount of gas. I thought he was crazy, and enjoys wasting time. Now he has me curious.... I went to fill the ST, pending the hurricane of death, IKE. I got it as close to $3.659999999 as I could, it flipped to $3.66, and STILL wasn't ONE gallon of gas.............$3.669999999 was one gallon..... Granted not so much, but when you add up all these folks everyday, every week, every month..... not bad.... Am I missing something here?? Isn't this illegal?? Or am I just tired, and incoherent, which wouldn't be far from the truth!!!! Thanks!![Broken External Image]:

 

[Carey Frennier]

hmm. I wonder if they're allowed a certain margin of error.

 

[Bill V]

There's nothing wrong, and no margin of error--the pump is correct.



$3.659/gal, times 0.999 gallons, is $3.655341. Rounded to the nearest penny is $3.66.



.998 gallons would still be rounded up to $3.66. At .997 gallons, you're now at 3.648023, which should theoretically round down to $3.65.

 

[EddieS'04]

I wish they would drop that 9/10 of a cent. What is the pupose of it anyway??

 

[Thomas Rogers]

I assumed the pumps rounded down (truncate) that last penny of the sale, but clearly they round up.



Which to me is stealing. Not sure how else to look at it. I pay money, I get no product...stealing!



Note, it's only a fraction of a penny on the total sale, not each gallon...or so I hope.



TJR

 

[TomT]

I wish they would drop that 9/10 of a cent. What is the pupose of it anyway??

I hear you Eddie. It was all well and good when we were paying 29.9 cents a gallon but it's kind of ridiculous these days.

 

[Bob Alcaro]

I believe it was on this site some time ago, that someone suggested a good way to verify the gas pump pricing and if it was rounding up each gallon or the overall sale.

The suggestion was to stop the pump after exactly 10 gallons was pumped into your vehicle, the price then should be exactly 10x the per/gal price.

ie: $3.659 per/gal

x10 gals......

= $36.59......

At this point it may round up (or not)!

 

[Ray McIntireJr]

Actually depending on the state they are allowed a certain % of margin of error. That is the thing, it varies greatly from state to state on the margin of error and the amount of time the agency that checks the pumps has to perform the testing. I saw something on the news not long ago about this.

 

[Andy Chase]

Or you could do it the old fashioned way of taking the total sale and divide by the gallons you put in!!! All you need is a calculator. Probably easier than pumping to 10.000 gallons on the dot.

 

[Thomas Rogers]

Raym2, I read the same thing about margin of error, but what is shown above isn't a margin of error, it is rounding up. The margin of error comes in to play when comparing what the pump says it dispensed (.999 gallons) and what the pump actually dispensed (could have been anything within the margin of error...which can be up to 2% in some states).



TJR

 

[Les]

Waaaaaaaaay too much time on your hands...

 

[Bill V]

raym, the "margin of error" to which you refer is regarding the determination of the volume of gas. It has to do with how the pumps measure the amount of fuel to have passed through the nozzle.



Once that volume is determined, however, there is no "margin of error"--it's the volume measurement multiplied by the price per volume. The only "margin of error" remaining is regarding the rounding off of partial pennies. I assume that in most states, the law requires rounding to the nearest penny--less than half a penny gets rounded down, more than half a penny gets rounded up.



TJR, to me, rounding to the nearest penny isn't stealing, so long as it's balanced, where you have a 50% chance of getting rounded up, and 50% chance of getting rounded down. It happens on anything bought in bulk--from gas to bananas to gravel. But even if the amount were always rouded up, the value of the gas in question would be miniscule compared to the value of gas involved in the margin of error on volume measurement. I'd question that long before I'd question any rounding effect...

 

[Brendan Grant]

As stated above. I would worry more about the volume of gas being less than what the pump registers. Have your buddy take a graduated cylinder out and measure a gallon of pumped gas from a gas can. I have encountered an occasional rural station when running on fumes that filled my tank with almost a gallon more on the display than the design specs on my gas tank. 21 gallons in a 20 gallon tank is a five percent measuring error in their favor.

 

[Thomas Rogers]

Bill V said:

TJR, to me, rounding to the nearest penny isn't stealing, so long as it's balanced, where you have a 50% chance of getting rounded up, and 50% chance of getting rounded down.

I didn't say nearest. I said "rounded up", as in "always rounded up." If everything between .00 and 004999999... was rounded down and everything between 0.0050 and 0.00999999... was rounded up, then I would be fine with that. But I doubt that's how it works. I'm a skeptic and I assume the pumps are rounding up in all cases. Of course, I don't know that.



TJR

 

[Richard L]

Since gas at that pump is $3.659 per gallon, and the pump only shows dollars and whole cents, it rounds up the sale price to the next penny as soon as $3.655 worth of gas was pumped.



Not illegal, but is profitable to the gas stations. Why do you think they always charge that extra 9/10 of a cent per gallon. The smaller the amount of gas you purchase, the more likely it will round up in their favor. If you buy 20 gallons of gas, they still can only can make a maximum of 1/2 of a cent on the round up.



...Rich

 

[Bill V]

I didn't say nearest. I said "rounded up", as in "always rounded up." If everything between .00 and 004999999... was rounded down and everything between 0.0050 and 0.00999999... was rounded up, then I would be fine with that. But I doubt that's how it works. I'm a skeptic and I assume the pumps are rounding up in all cases. Of course, I don't know that.



TJR

Fair enough. I knew you had said "rounded up", but I misunderstood you to be saying that the photo which started this thread demonstrates that the price was rounded up in this specific instance. As shown in the math I posted in the third message of this thread, we really have no evidence either way regarding whether prices in this case are "rounded off" or "rounded up", as the price in this instance would be rounded to $3.66 using either method. I personally suspect that the law in most, if not all, states would require them to be "rounded off".

Since gas at that pump is $3.659 per gallon, and the pump only shows dollars and whole cents, it rounds up the sale price to the next penny as soon as $3.655 worth of gas was pumped.



Not illegal, but is profitable to the gas stations.

Richard L, how do you figure that this is profitable? Yes, it rounds up if the net sale ends in more than half a penny. But if you assume that it rounds down if the net sale ends in less than half a penny, they lose, on average, just as much money on those sales as they make money.

Why do you think they always charge that extra 9/10 of a cent per gallon.

The reason has everything to do with marketing. People are likely to think that gas prices are lower than they really are if they see it 1/10th of a cent less, and that makes them more likely to stop and purchase gas at their store. On a subconscious level, $3.499 looks a lot cheaper than $3.50 to most people, even though they're only one-tenth of a cent apart. It's the same reason so many stores will price something at $9.99 instead of $10.00--to the typical consumer, on a subconscious level, the difference looks like a whole lot more than a penny.

If you buy 20 gallons of gas, they still can only can make a maximum of 1/2 of a cent on the round up.

Like I said earlier, they can also lose a maximum of 1/2 of a cent. It all comes out in the wash.

 

[Bill V]

Even if they had a practice of rounding all partial pennies up to the next cent, the difference is still minute compared with the potential gains/losses from the margin of error in the pump's volume measurement. According to an unscientific sampling of information I could find on the web, most states allow stations a tolerance of +/- 6 cubic inches (which is about four tenths of a cup) on a five-gallon sample. With 231 cubic inches in a gallon, or 1155 cubic inches in five gallons, that's a tolerance of +/- 0.52%. If you use a price of $3.60/gallon, that's an error of up to +/- $.0187/gallon. Fill a tank with 20 gallons, and that's a completely legal measurement tolerance error of up to 37.4 cents per tank--again, either for or against the station, depending on which way the error runs.



Like I said, by comparison, the rounding of half a penny (or even of a whole penny, if you assume they round up) is small enough to be practically irrelevant in comparison.

 

[Thomas Rogers]

Bill V said:

Even if they had a practice of rounding all partial pennies up to the next cent, the difference is still minute compared with the potential gains/losses from the margin of error in the pump's volume measurement

Agreed. I never discussed margin of error until it was brought up, and certainly didn't mean to imply that rounding up was a significant amount or greater than the margin of error discrepancy.



However, if you took all those fractions of pennies from all the customers, each day, all year long, across all stations throughout the nation and added them together, then you begin to get as much money as the movies "Superman III" and "Office Space" made together.







TJR

 

[Jimmy Lavoie]

I LOVE OFFICE SPACE!!



Sorry, went off topic for a sec. :blink:

 

[Bill V]

Superman III--$59,950,623 domestic box office gross

Office Space--$10,827,810 domestic box office gross

Total--$70,778,433



OK, yeah, that's some decent coin.



(Yes, I know that's not what you meant.)