You have two vehicles: one gets 10 miles per gallon, the other gets 20 miles per gallon.
You have the option of upgrading one. The first can go from 10 to 20 mpg, while the second can go from 20 to 50 mpg.

Which one do you choose?


Although I believe the results will be skewed here versus the general public, I still want to see how this lays out.

[edit] Both vehicles are driven equal number of miles

Anyone who votes the first option is probably someone like sab or the kind of ****** that bought a Hummer.

Is the first option substantially faster than the second? If so I take the first.

The first one.

Anyone who votes the first option is probably better at math than Baconfish.

But Jon, what if a number of people in urban areas all decide that the second option is better?

I feel like there's something I'm missing.

Car #1:
100 miles = 10gallons/5gallons (before/after upgrade)
Increased efficiency: 2x.
At $2 gallon = $20/$10.
Cost change: 50%

Car #2:
100 miles = 5g/2g
Increased efficiency: 2.5x
At $2 gallon = $10/$4.
Cost change: 60%

I really feel like there's a trick question here... but I can't find it... Unless the trick question is a lot of people are dumb and would pick the first one.

Apparently, they're better at math than me, too. 10to 20 doubles the mileage, where 20 to 50 MORE than doubles it. Now, math isn't my best subject, so if I'm wrong, someone please explain it to me.

The second option is only better if you put the first car on cinderblocks.

I think the point is you still have two cars. Is it better to have two vehicles that get 20mpg or one that gets 50mpg and one that gets 10.

Suppose you drive both vehicles the same amount.

You drive the first car 100 miles, which requires 10 gallons. If you upgraded, you would require 5 gallons. That means you save 5 gallons of gasoline.
You drive the second car 100 miles, which requires 5 gallons. If you upgraded, you would require 2 gallons. That means you save 3 gallons of gasoline.

You save more fuel by upgrading the first vehicle.

Seeing as it's listed by mpg it's fairer to look at it from a perspective of mpg rather than gpm.

Seeing as they're two ways of measuring the same amount it's fairer to look at it from a perspective that actually corresponds to reality.

nvm

This is the answer and explanation I was looking for.


Upgrade worth the money, hence why I said you have two cars but can only upgrade one.

I chose second not because I think it's better for gas mileage, but because:

If I even own a 10mpg car, I obviously don't drive it much as is, as it's probably some big truck or sports car. Thus, I'd rather just have the performance or utility as a standby. I'd much rather use the higher mpg car for daily driving, where it would easily make up for the gallon usage discrepancy.

Edit: Since the thread stated nothing about picking a poll option based on the idea that they'd both be driven equally, I stand by my choice.

Ok then, I'll take the one that results in me saving more fuel starting from scratch rather than starting with 10mpg.

Personally, the efficiency of my car would affect how often I drive it. So assuming I'd drive both cars equally doesn't really work.

Added a line that both drive the same number of miles to counter CM's reasoning that he'd drive the guzzler less. But just because that's a nicer option to leave the guzzler at home doesn't mean it's practical. Contractors or manual laborers may need their truck for daily use at work and have to leave their sedan at home.

Yeah see that line completely changes the nature of the poll. Jood gob.

****in 'burgher

If I have 2 vehicles and one of them gets 10mpg it's more than likely a Ferrari, I drive this very rarely.

If my 2nd car gets 20mpg maybe it's an M5 (I dont know there mpg rating just making a point) and it's my daily driver so I put a lot more miles on it.

2nd option.

Basically this poll is supposed to show how people intuitively misunderstand the function 1/x. e.g. going from 50 mpg to 80 mpg sounds impressive, even though the fuel savings are almost nothing (1%.)

That's why car manufacturers use mpg instead of gal/mi. They're exploiting a psychological flaw in all people. If you're aware of it, you don't fall for marketing gimmicks like this.

Yeah, but it helps clarify the issue. People just assumed the second one would be the primary mode of transportation, so whatever the upgrade and regardless of how much of a rip-off it was, money would still be saved on gas if they drove infinite miles.

edit: actually not infinite, a really large number of miles.

I don't understand how THIS thread was resolved basically immediately, and yet planes on treadmills went on for pages and pages, even though planes on treadmills is blatantly obvious and this one requires some thinking/calculating.

However, I completely enjoyed this question.

It's only blatantly obvious if you know how a plane works, or rather how a plane doesn't work.

I'm still a little shocked at the poll results.

It's early. **** you all

If going by the idea that both cars are driven equally and both are necessary, then option 1.

If going by the idea that one car is primary transportation and the other is secondary/luxury, I would sell car 1 and upgrade car 2. (because I have no use for multiple vehicles)

I didn't see the little both cars are driven equal miles qualifier.

What Jon'C explained still would have flown right over my head quite honestly though.

Okay, remember my previous post, right? Let's suppose you don't drive the two vehicles the same amount.

For notation, suppose the gas-guzzler is a truck, and the other vehicle is a car. Let's name our options:

Option A: Upgrade the 10 mpg truck to 20 mpg. That means you save 0.05 gallons for every mile you drive the truck, and 0 gallons for every mile you drive the car.
Option B: Upgrade the 20 mpg car to 50 mpg. That means you save 0.03 gallons for every mile you drive the car, and 0 gallons for every mile you drive the truck.

As I showed above, if both vehicles are driven the same amount, you save more fuel by choosing Option A. But Option B "feels" right - we don't drive the truck very often, after all. Let p represent the proportion that the truck is driven (equivalently, 1-p represents the proportion that the car is driven.) I want to find p such that Option B is better than Option A. This is a simple inequality:

p0.05 + (1-p)0.00 < p0.00 + (1-p)0.03
<=> p0.05 < (1-p)0.03
<=> p < 0.375.

You would need to drive your truck less than 37.5% of the time for Option B to be at least as good as the alternative. Maybe this is still realistic, but it's clear that Option A is superior outside of deliberately-contrived usage situations.

Driving the two vehicles equal amounts of time is no less 'deliberately-contrived'.

Why don't you just say that it depends on usage, instead of beating your 'urdum' drum some more?

Some people handle it better than mailmen with unwarranted egos.

ok i think i definitely see how in terms of math, option A wields a larger increase in savings if both vehicles are driven about the same amount.

however in practice if i had a truck and a sedan, i would only be driving the truck maybe 10% of the time... MAYBE.

I filled up two of my vehicles the other day. $50 of premium in the car (yes, the owners manual calls for premium) and $115 of diesel in the truck. Can't wait for $5 per gallon fuel to get here!

And, no, this has nothing to do with the math question.

To be fair, the question changed radically when you stated that we drive the cars equally. Without that stipulation, I simply wouldn't drive the truck - or at least I'd only drive it when I really really needed a truck (which is maybe 3 times a year). So the whole poll is void, because a ton of answers were submitted before the question was clarified.

The problem is that "you have two vehicles" did not compute. I would never have two vehicles.

Jon already explained that even without driving the cars an equal amount option A is a better choice more than 62.5% of the time.

That doesn't preclude the very strong possibility that people will do what happydud describes. I know I would. It's a simple misunderstanding of the point of the problem, brought about by a lack of one important detail. Maybe people would have been wrong, still, but the reason they're 'wrong' now is because they were thinking they wouldn't drive the other car.

(some of them)