Date: Tue, 23 Oct 2012 17:07:14 -0700 From: Gary Kline <kline@thought.org> To: Polytropon <freebsd@edvax.de> Cc: Olivier Nicole <olivier.nicole@cs.ait.ac.th>, FreeBSD Mailing List <freebsd-questions@freebsd.org> Subject: Re: way way off topic Message-ID: <20121024000714.GG29440@ethic.thought.org> In-Reply-To: <20121023085249.5c742ccc.freebsd@edvax.de> References: <20121023042007.GA14738@ethic.thought.org> <CA%2Bg%2BBvgaYY-nh9d89a7ytf9RAgMSjFNHPh3GzNqNG0xPFEX9BQ@mail.gmail.com> <20121023085249.5c742ccc.freebsd@edvax.de>
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On Tue, Oct 23, 2012 at 08:52:49AM +0200, Polytropon wrote:
> On Tue, 23 Oct 2012 11:31:18 +0700, Olivier Nicole wrote:
> > Gary,
> >
> > On Tue, Oct 23, 2012 at 11:20 AM, Gary Kline <kline@thought.org> wrote:
> > >
> > > apologies up front for this math type quandary. I had it in a std C program,
> > > but 3+ hours of grepping havent found it. I would have bet my last cent that I
> > > had a summary Somewhere, but cant find that either.
> > >
> > > here is the problem as best I can remember it.
> > >
> > >
> > > let's say that john is 8 and his older friend, jim, is 22.
> > > how much older is exact percentage terms is jim?
> >
> > That should be 22/8=2.75
> > Jim is 275% older than John
>
> Jim is 175% _older_. Why? Because 100% older means 16 years,
> as 100% refers to 8 years (8+8=16, 200% older is 8+8+8=24).
> Percentage is always a reference to something else, in this
> question, Jim's age in relation to John's. The word "older"
> means "adding percentage", refering to the base value of 8,
> "divided in 100 parts" (floating point considerations aside),
> to finally reach the value 22.
>
> If the question would be different, say, "What's the percentage
> of John's age regarding Jim's age?" In that case, it would be
> 8/22=0.3636 being 36%. Obvious: John's age is approximately
> 1/3 of Jim's age.
>
> The easiest way for creating the proper calculation is to refer
> to the equation
>
> percentage * 100
> percentage value = ----------------
> base value
>
> and resolve it to whatever is required.
>
> --
> Polytropon
> Magdeburg, Germany
> Happy FreeBSD user since 4.0
> Andra moi ennepe, Mousa, ...
yo; I THInk this is it. around line 4542 in my ~/.HowTo file::
%%% find percent inc/dec [increase/decrease] between two numbers.
Always figure the percentage of change relative to the original value!
For instance: * Suppose a certain item used to sell for seventy-five
cents a pound, you see that it's been marked up to eighty-one cents a
pound. What is the percent increase?
First, I have to find the absolute
increase:
Reserved 81 - 75 = 6
The price has gone up six cents. Now I can find the
percentage increase over the original price.
This percentage increase is the relative change: 6/75 = 0.08
...or an 8% increase in price per pound.
So I was wrong about ages or speed; it's the % betwen two ints;
here, the inc/dec [or change] between 75 cents as compared to
an inflated increase of 81 cents.
1. find abs increase: 81-75 = 6;
2 find the % increase over the *original* value. 6.0/75.0
3. percent increase using doubles is 0.08; so a markup of six
cents is an 8% rate.
so: going back to the ages example with john bein 8, jim, 22.
22-8 is 14.
14.0/8.0 = 1.750000
175%. jim is 175% times older than john. which is what you found,
polyt. {I'll have to re-read your logic now that im awake..}
Or, how much more, in % is 16t than 15, it is 1.0/15.0 which is 6%.
etc, etc.
Hm. that's 0 for gary, 729 for polytrop!!
Ah, life:: accept no substitutes.
--
Gary Kline kline@thought.org http://www.thought.org Public Service Unix
Twenty-six years of service to the Unix community.
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