Numbers for Everyone

More on gas prices

2008-07-24T15:37:00.008-04:00

Do you drive around for low gas prices? If a station offers a nickel-a-gallon discount for cash, do you pull out your Jacksons? Do you drive the first vehicle in the driveway?

With the price of gas passing $4.00 a gallon, you should rethink all these activities. It's a matter of percentages.

(For these calculations, we will assume the average car gets 25 MPG in a 15 gallon fillup and pays about $4.00 / gallon. As the price goes up, your mileage goes down, or you pump less gas at a stop, the logic gets stronger.)

If you get off your customary route to pay $3.99 rather than $4.05, you're saving 6c per gallon. With that fillup, you've saved $.90. That will buy you less than 1/4 gallon more or about 5.5 miles. That may be more than around the block, but it won't justify going to the next interstate exit and back.

The same numbers apply to savings for cash. Of course, if your credit card gives you a 1% or 3% rebate, not many stations will give that much discount. 3% of $4 is 12c. This assumes you pay off your credit card without interest. If you pay the bank 3 or 4 months' interest at 9% APR (a good rate; some people pay two to three times that), you've more than lost your 3% rebate.

Which car do you drive? If you have one car that gets 22 MPG and another at 27 MPG, should you make an effort to drive the more efficient one? If you have a 10 mile one-way commute, you'll save about $.67 per day. That may not sound like much; but come Friday, it's another beer at happy hour. Obviously a bigger spread means more money. Here we're talking about a 22% difference; 5 MPG is a bigger percentage if you're starting with less but only 13% between 42 and 37 MPG cars.

Download the spreadsheet for your own calculations.

(c) 2004-2008 Bill Barnes w/ public domain components. Free distribution with permanent acknowledgment.
More like this: http://3500a.blogspot.com/

Can the government lower gas prices?

2008-06-26T09:56:00.005-04:00

Tax moratorium. Open the Strategic Petroleum Reserve. Encourage new refinery construction. Fast-track domestic drilling permits.

As gas approaches $5 per gallon it seems everyone in and out of politics is pushing their favorite scheme for Washington to push prices down. They're all likely ineffective in the current free-market economy. Short of an explicit cap on retail prices - something that is never seen in this country - any administrative action to reduce wholesale costs will have minimal effect at the retail end.

Beside the policy debate, cutting taxes or releasing federally owned crude (presumably at a price well below market or cost) would have a minimal effect on the price at the pump. Even if the entire value of the stimulus ended up in the consumer's pocket, it would not return us to even 6-months-ago prices. The federal tax is 18c/gallon. Giving away 5% of US consumption from the SPR would deplete the reserve in less than two years and cut prices by only 25c/gallon. Whether either of these discounts makes it to the nozzle is problematical in a free market.

In my opinion, the other two schemes to attempt to influence the market face ethical challenges over economics. They require that current Americans run even more roughshod over the rest of the world and the future than we already are.

Some pundits claim that US refineries are running flat out and couldn’t produce more product if the input were available. Capitalism says anything can be done, if you’re willing to pay the price. Instead advocates want a defacto subsidy to expansion, either monetary or by relaxing pollution and safety requirements for an industry that already has plenty of problems in those areas.

And yes, relaxed regulations could allow more oil to be pumped on US territory. One writer stated that he knew energy companies can work safely and drill the outer continental shelf without any risk of direct environmental damage. I agree, but that is not the point. On the one hand, we fret about human-induced climate change; but on the other laments that we need to produce more oil to reduce the price so we can burn more oil … . If we are serious about passing a livable world on to future generations, we shouldn’t be trying to use a few more gallons today.

Economics should provide an eventual resolution to the question of gas prices – albeit one that may not be to the liking of current complainers. All commodities should reach an equilibrium price based on supply and demand. As prices go up, producers will find or redirect more supply. Also as prices go up, consumers will reduce their demand forcing suppliers to cut the price to justify their infrastructure. Eventually everything will balance out.

If you object to what a seller is doing – whether it’s raising prices or building an ugly store in your neighborhood – the free market response is to stop giving that seller your money. You can force gas prices down by buying less – change your driving habits or change your vehicle to use less gas per mile.

RESOURCES:
SPR
Daily oil demand

Excel Auto-fill and Formatting demo

2007-09-27T08:50:00.000-04:00

This spreadsheet has some interesting features on page BadgeLog. Because this spreadsheet uses many Excel features, I offer it as a download.

• The formula in N7 was fun. I create the logon ID from the first letter of the first name and the last name. BUT, I don't create this ID until I've entered the date to verify that I've actually created the account. The other blue column is also automatically filled.

• 4 columns (green) contain drop-downs created with the Data > Validation tool and data on the Lists page.

• I used Conditional Formatting to indicate the columns that are either auto filled or have drop-downs.

• There's a neat macro (which I didn't create from scratch) to automatically fill in the shading. After I delete lines or resort the spreadsheet, the macro clears existing formatting and recreates the shading. This one is hard-coded, but the original prompted for variables for many of the specs.

(c) 2004-2007 corp04@zaitech.com w/ public domain components. Free distribution with permanent acknowledgment.

Ratios

2007-08-18T17:20:00.000-04:00

With the advent of HDTV, all the reviewers talk about the new 16:9 screen ratio as opposed to the old - square - 4:3 ratio.

I always thought widescreen TV and widescreen computers were the same thing. Until I was trying to design a PowerPoint(r) presentation to show on a TV. I set the page size to 16x9 and it didn't fill my computer quite right. Then I looked at the actual resolutions.

HDTV is nominally 1920 x 1080 (pixels). My computer monitor is 1440 x 900. I could quickly divide and see that HDTV is 1.78:1 while the computer is 1.6:1. But how do these ratios compare - in integers?

I'll save you the suspense. HDTV is, in fact, 16:9. The computer turned out to be 16:10 - a little squarer so that a presentation to fill the TV will leave a little top and bottom on the computer.

Google Docs and Excel(r) have an advanced* function called =GCD - "Greatest Common Denominator". We all learned about the Least Common Denominator in the 4th grade, but what is GCD? It's the largest integer that will evenly divide both sides of a fraction. If you divide both sides of a fraction by the GCD, you get what I was looking for: a simple integer ratio.

You can download the worksheet+ as a picture or live Google Doc that you can use as your own. Either way, column J contains the formula (without the ' ) to fill in under the raw data.

* GCD may not work in Excel until you load the Add-In. From the Tools menu, select Add-Ins... and check Analysis ToolPak. When you click OK, it may ask for your original Office CD to load the component.

Miles per Gallon

2007-08-08T20:12:00.000-04:00

OK, maybe I'm compulsive about keeping trivial records. But with $3+/gal gas, everyone's starting to be interested in how they're doing day-to-day.

This workbook + contains one simple formula =(F8-F7)/E8 in col G to calculate MPG at your last fillup. Since you may not be consistent in how full you get your tank, I also included 2-tank and 3-tank averages to smooth it out.

My Audit column recalculates the cost as the price per gallon times the gallons to catch typos. If it's off by more than a few cents (to allow for the hundredths of a gallon), one of the numbers is wrong. Sometimes I know the audit is going to be invalid if I didn't actually fill up once and a "single tank" represents multiple purchases at different prices (this is common if I know I'm travelling to a low-price area, but need another 2 gallons to get there).

For MPG tracking to be accurate, you have to be faithful. If you regularly buy gas without filling up, you have to combine individual purchases to create a "tank" that you know all the miles were burned on.* And, if you forget to write down the gallons just once, not only is that tank invalid, but so is all your cumulative data. Like I said, I'm compulsive.

I haven't yet figured the simple formula (I can do it with programming) for row 1 to get an accurate average of all the non-0 entries in a column. If I set the average past the current bottom of the worksheet, it counts all the empty rows. As it is now, my "lifetime" is only to where I was last time I wrote the formula.

* If you don't fill up ...
You can only calculate MPG if you know exactly how many gallons you burned for a given number of miles. If you can only afford $5 at a time; one day that $5 may bring you up to 7/8 full and the next you leave the pump just 1/3 full. That means you burned more gas than you bought, but you don't know how much. If you occasionally miss a fill up, just add all the partials to the next time you top off and call it one "tank". If you never fill up ... well, your lifetime average will be close (because being off by 4 gal when you're calculating MPG for 400 gal isn't significant).

(c) 2007 Bill Barnes
More like this: http://3500a.blogspot.com/

+ To use the published workbook:
Click the link to open a web picture - not a working spreadsheet - of my workbook. Type the content from the Formulas page into a spreadsheet. The heading "Date" goes in cell B3. You only really need the five formulas on row 7 that start =(F7-F6)/E7. Then you can use your spreadsheet's autofill function to replicate them on the rest of your rows. Be sure not to type the " ' " before the "=".

Even easier; if you have a Google account, you can open a live spreadsheet in Google Docs. From there you can export it for your own use with the formulas intact.