KM vs Miles

[Andy in Germany]

km = (mi/2) + (mi/10) + mi
mi = (km/2) + (km/10) (plus a little bit for luck)

Could you do and example of this so I can understand it?

 

[pippy]

Of course, it’s only those who insist on using kilometres that make this necessary ;-)

True; but as the majority of myself and my family's friends hail from Continental Europe (and we, ourselves, spend quite a lot of time across La Manche) being able to ready-reckon any said distance in either system comes in rather handy!



Philip.

 

[Dogtrousers]

Could you do and example of this so I can understand it?

78

I want to know what 78km is in miles. Half of 78 is 39. A tenth of 78 is 7.8. 39+7.8 is 46.8 miles (Real answer is 48.4, so it's OK but not great. All I've done is multiplied it by 0.6. It's not hard to add a the missing bit but I won't do that here)

I want to know what 78miles is in km. Do the above and get 46.8. Now add the original 78. 124.8 km. (Real answer is 125.5. Not bad. All I've done is multiplied it by 1.6).

Maybe I have a weird brain but I find this really easy. It comes from years of running 10ks and half marathons, and riding 100km and 100 mile rides and thinking about such things to pass the time. Other people have their own pet methods and prefer them. I'm not saying this is a good method or that others should use it. It just happens to be what I do. If you don't like it, fair enough, I'm not asking you to.

 

[pippy]

Could you do and example of this so I can understand it?

If I might answer?

It's actually a rather good system involving simple sums. Let's take a distance of ten miles to be converted into kilometers.

Using the equation (x)km = (mi/2) + (mi/10) + mi (where 'x' is the unknown) we get;

'x' km = (10 / 2) + (10 / 10) + 10

Therefore 'x' = (5 + 1 + 10) = 16.

Ergo 10 miles = 16 kilometers.

Philip.



I see Dogtrousers and I were cross-posting...apologies to them for my butting in!

 

[Andy in Germany]

Maybe I have a weird brain but I find this really easy. It comes from years of running 10ks and half marathons, and riding 100km and 100 mile rides and thinking about such things to pass the time. Other people have their own pet methods and prefer them. I'm not saying this is a good method or that others should use it. It just happens to be what I do. If you don't like it, fair enough, I'm not asking you to.

If I might answer?

It's actually a rather good system involving simple sums. Let's take a distance of ten miles to be converted into kilometers.

Thanks, that's really helpful.

It's not a matter of scepticism about the system; more that I can't generally understand formulas unless I see an example, and often even then I don't really understand what they "mean". I'll learn a formula by rote and practice obsessively because I know that if I follow the steps and keep the units, the number at the end is usually what the examiner wants.

As an example I'm currently practicing the formula for amps, volts and ohms. Fortunately I can generally select the correct formula because here they use a visual system, but I still don't really understand what I'm doing.

However, a week after the exam I probably can't use the formula any more: I'll have forgotten it entirely.

 

[classic33]

If I'm measuring a wall, I think I'll carry a tape measure rather than take my boots off...

You can leave yer boots on if yer've size ten(UK) feet/safety footwear.
Heel to toe over ten foot you'll be less than an inch over.

 

[brommieinkorea]

If I'm measuring a wall, I think I'll carry a tape measure rather than take my boots off...

No, you have to have your boots on.

 

[Punkawallah]

Thanks, that's really helpful.

It's not a matter of scepticism about the system; more that I can't generally understand formulas unless I see an example, and often even then I don't really understand what they "mean". I'll learn a formula by rote and practice obsessively because I know that if I follow the steps and keep the units, the number at the end is usually what the examiner wants.

As an example I'm currently practicing the formula for amps, volts and ohms. Fortunately I can generally select the correct formula because here they use a visual system, but I still don't really understand what I'm doing.

However, a week after the exam I probably can't use the formula any more: I'll have forgotten it entirely.

Or you could just remember 10k is about 6 miles, and figure from there?

 

[MontyVeda]

Or you could just remember 10k is about 6 miles, and figure from there?

half it, add a quarter and round up a bit... is my method of getting near enough.

10k / 2 = 5
5k / 4 = 1.25
=6.25... then round it up a bit

 

[Sea of vapours]

half it, add a quarter and round up a bit... is my method of getting near enough.

Eh? You need to round it *down* a bit, not up. 10km = 6.214 miles.

 

[MontyVeda]

Eh? You need to round it *down* a bit, not up. 10km = 6.214 miles.

always had it in my head that 1km was .64mile... ah well. i'll just not bother rounding at all... it's near enough

 

[annedonnelly]

As an example I'm currently practicing the formula for amps, volts and ohms. Fortunately I can generally select the correct formula because here they use a visual system, but I still don't really understand what I'm doing.

However, a week after the exam I probably can't use the formula any more: I'll have forgotten it entirely.

Is it still V=IR ? Ohm's Law. Unlike you I've remembered that for many years, but I'm definitely not a visual learner. I was always very good at memorising things and maths and physics came very naturally to me.

 

[Andy in Germany]

Is it still V=IR ? Ohm's Law. Unlike you I've remembered that for many years, but I'm definitely not a visual learner. I was always very good at memorising things and maths and physics came very naturally to me.

That's the one. I remember it as a triangle with the letters inside: plan is to go into the exam and immediately write the formulas down ready for use. The one for calculating spoke sizes may not work, to be fair, as it's a tad complex: I'd hate to be doing that one in imperial measurements...

My inability to remember numbers is compensated by being able to remember things like cycling routes when I'v e used them once, and being able to design things in my head and view it from different angles.

 

[MontyVeda]

That's the one. I remember it as a triangle with the letters inside: plan is to go into the exam and immediately write the formulas down ready for use. The one for calculating spoke sizes may not work, to be fair, as it's a tad complex: I'd hate to be doing that one in imperial measurements...

My inability to remember numbers is compensated by being able to remember things like cycling routes when I'v e used them once, and being able to design things in my head and view it from different angles.

my memory ain't great but i seem to recall W,A,V and V,A,R.... but all I've ever used is watts / volts = amps... to work out why two electric heaters partially melted an extension lead