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From: kami <f00@0f0.00f>
Newsgroups: sci.lang,alt.usage.english
Subject: Re: OT: Converting miles/km
Date: Sun, 22 Sep 2024 09:28:47 -0000 (UTC)
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On Sun, 22 Sep 2024 01:52:33 -0700, Snidely wrote:

> Remember when kami bragged outrageously?  That was Sunday:
>> On Thu, 19 Sep 2024 23:12:52 -0000 (UTC), Christian Weisgerber
>> wrote:
>>
>>> I'm sorry, I don't know where to post this.  I'm crossposting to
>>> alt.usage.english, because statute miles as a unit mostly afflict
>>> the English-speaking world.
>>> 
>>> So you want to convert between miles and kilometers.  The conversion
>>> factor is... uh...  A 40-year-old calculator book provides a useful
>>> tip:  Unless you're designing a space probe, you can use ln(5).
>>> 
>>> WHAT?
>>> 
>>> Yes, the natural logrithm of 5 approximates the conversion factor
>>> between miles and kilometers; specifically one mile is about ln(5)
>>> kilometers.  It's accurate to four digits.
>>> 
>>> If nothing else, it's faster to type on a calculator.
>>> 
>>> I think that's hysterical.
>>
>>
>> simplest method is to multiply by 0.6
> 
> There's no humor in that.
> 
> -d

an easier method would be, if the limit is 80 miles per hour,
simply add half, which is 40 and then one tenth of that, which is
4 and multiply it by 2 which is 8, so 48 + 80 is 128 km/h

similarly lets say 120 miles per hour, half 60, tenth times 2 is
12, so 72 + 120 = 192 km/h.