Does the answer annoy you?

VFM Addict

VFM Addict

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Its an old maths question but even though I know the answer it still annoys me 'cos it just doesn't feel right. Here it is.

I set off on a two mile journey. I do the first mile at 30mph. At what speed must I travel the second mile to average 60mph for the total two mile trip?
 
The speed of light... And then, only from your perspective (you would still be slower than 60mph average from the point of view of an external observer).

Is this some kind of trick question with clever wording, or is it something else I'm missing? :confused:
 
Duff-Man said:
The speed of light... And then, only from your perspective (you would still be slower than 60mph average from the point of view of an external observer).

Is this some kind of trick question with clever wording, or is it something else I'm missing? :confused:
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No you're not missing anything. The maths are very simple. To avg. 60 you must do two miles in two minutes but you've used up the whole two minutes doing the first mile.

It wasn't the maths I was asking about. What I was saying is does it kinda niggle you that no matter how damn fast you go, even if you exceeded the speed of light, you still couldn't average just 60mph for the trip.

I know its right it just doesn't feel right through. It annoys me......:mad:
 
You word a scam/puzzle, then give the answer which is countered by your wording.

And this confuses you?

VFM Addict said:
I set off on a two mile journey. I do the first mile at 30mph. At what speed must I travel the second mile to average 60mph for the total two mile trip?
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90MPH

VFM Addict said:
To avg. 60 you must do two miles in two minutes but you've used up the whole two minutes doing the first mile.

even if you exceeded the speed of light, you still couldn't average just 60mph for the trip.
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Erm what?
 
platinum87 said:
You word a scam/puzzle, then give the answer which is countered by your wording.

And this confuses you?

90MPH

Erm what?
Click to expand...

No...

Suppose you did travel the second mile at 90mph. The first mile took you two minutes, the second took 40s. The total travel time is 160s for two miles, which is 80s per mile average: An average of 45 Mph.


...As mentioned above, I don't see anything that isn't intuitive here. The second mile must be travelled instantaneously. I spent a while looking for clues in the question wording that the answer might be otherwise (i.e a trick question), but there is none.
 
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Why not do 120mph the second mile? That should average out approximately as it doesn't say you do 2 miles in 2 minutes...

EDIT: Ahh it's an exponential?
 
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Actually 90mph is wrong, my brain is off.

So basically 2 minutes to do 1 mile @ 30mph

to average 60mph over 2 miles you need to complete it within 2 minutes
Thus it is impossible
 
platinum87 said:
You word a scam/puzzle, then give the answer which is countered by your wording.

And this confuses you?

90MPH

Erm what?
Click to expand...

What the hell the 90mph is doing the middle of your post really confuses me.

I thought my thread title was clear. Do you find the answer - that no matter how damn fast one travels you still can't average just 60 damn mph - annoying. I always have. I know its right. But it just doesn't feel right, if you know what I mean.

EDIT - You posted before I did. I now see why the 90mph was there.
 
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You can never average 60 mph on that journey, 60mph is a mile a minute, you only have 2 miles to travel thus you only have 2 mins to do it in and you used them both during the first mile.
 
VFM Addict said:
What the hell the 90mph is doing the middle of your post really confuses me.

I thought my thread title was clear. Do you find the answer - that no matter how damn fast one travels you still can average just 60 damn mph - annoying I always have. I know its right. But it just doesn't feel right, if you know what I mean
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Yea i know ignore that, my brain was off

The answer is Infinite speed.

I know thats cheating but what the hell

Edit, This is great to wake people up FYI....
 
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LOAM said:
You can never average 60 mph on that journey, 60mph is a mile a minute, you only have 2 miles to travel thus you only have 2 mins to do it in and you used them both during the first mile.
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It doesn't say anywhere that it must be completed in exactly 2 minutes though?

Theoretically it's possible, assuming one can change and match speeds at any given instant in time...
 
bJN said:
It doesn't say anywhere that it must be completed in exactly 2 minutes though?

Theoretically it's possible, assuming one can change and match speeds at any given instant in time...
Click to expand...

It isnt possible.

It doesnt have to say 2 minutes. A question for you.... If you travel at a constant speed of 60mph, how long will it take to do 2 miles?
 
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