IraceBLOG

Discount Acomplia Get High Where Order Flomax Mexico Purchase Soma SaintPaul Elavil Shop Where To Get Hoodia Germany Penisole Online Clomid Dosing Where Order Stromectol For Add Where Order Flomax Side Effects Cipro Dosage Discount Levitra Description Generic Antabuse Charleston Herbal Cymbalta Equivalent Lexapro Effects Generic Elavil Prescription Sale Lipitor Plavix Generic Neurontin Boise Price For Lasix Proper Dosage Hoodia Seroquel Online Plavix Online Clinic Sale Lotrisone Where To Get Doxycycline Prescription Where To Get Prednisone Mexico Where To Get Cipro Canadian Where To Get Amoxil Forum Purchase Zelnorm LittleRock Where Order Elimite Prescription Purchase Ultram Topeka Herbal Topamax Horny Goat Weed Where To Get Nexium Tablets Buy Topamax Cheyenne Where To Get Clomid Comparison VPXL Flomax Equivalent Where Order Prevacid Free Samples Where To Get Stromectol Spain Where To Get Propecia Effects Order Lexapro Charleston Herbal Toprol XL Get High Buy Cytotec Lexapro Dosing Where To Get Aricept Weight Acomplia NoRX Where To Get Levitra Mexico Erythromycin Weight Natural Tramadol Get High Generic Zelnorm Honolulu Order Neurontin

When I rent a car, how many miles I must drive per day to justifythe added cost of choosing a spiffy, high-tech, environmentally friendly Toyota Prius considering the extra rental cost, the hybrid’s fuel economy and the cost of gas? Let’s do a little math!

let $c\!$ = the cost of gas for a given distance of travel (in dollars).

let $p_1\!$ = the mileage of a conventional car (in miles per gallon).

let $p_2\!$ = the mileage of the Prius (in miles per gallon).

let $d\!$ = the distance traveled in one day (in miles).

let $v\!$ = the cost of gas (in dollars per gallon).

let $x\!$ = the daily extra rental cost of a Prius over a conventional car (in dollars).

Let’s begin by figuring out the relationship between all these units of measurement.

$$ = \frac{$}{gallon} \times \frac{gallons}{mile} \times miles$

Now can show the relationship between all our variables.

$c = v \times \frac{1}{p} \times d$

which simplifies to

$c = \frac{vd}{p}$

Finding the break-even driving distance (of rental fees plus fuel cost) means calculating $c\!$ for the conventional car, $c\!$ for the Prius (plus $x\!$ , the additional Prius daily rental cost), creating an equation making them equal and solving for $d\!$ . Here we go!

$\frac{vd}{p_1} = \frac{vd}{p_2} + x$

Solving for $d\!$ requires a little bit of high-school algebra.

${p_2}vd = {p_1}vd + {p_1}{p_2}x\!$

${p_2}vd - {p_1}vd = {p_1}{p_2}x\!$

and

$vd(p_2 - p_1) = {p_1}{p_2}x\!$

finally:

$d = \frac{{p_1}{p_2}x}{v(p_2 - p_1)}$

I rented a Prius today and averaged 45 MPG with it. The rental cost me $6
more than the car I would have otherwise ended up with, say a Chevrolet Cobalt (ugh, pfft, ackpth) with an EPA city mileage rating of 22 MPG. Today’s gas price was $3.89. Was it worth it?

$d = \frac{22 \times 45 \times 6}{$3.89 \times (45 - 22)} = \frac{5940}{89.5} = 66$

I would have had to drive 66 miles per day for the Prius upgrade to make financial sense. I drove 65, so I’m calling that good enough. My smug emissions are justified!

Plus I wasn’t driving around in a Chevy Cobalt. Eww.

…a second decade of cheese sandwiches.

Book Report: Carl Sagan, The Varieties of Scientific Experience:

Comcast "High Definition" Isn't:

Happy 90th Birthday Grandad!:

A little environmental math

More Blinkenlights!

I downgraded our stereo

Geocoding: Easier than you think

More silliness