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 <kl...@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 kl...@thought.org http://www.thought.org Public Service Unix Twenty-six years of service to the Unix community. _______________________________________________ freebsd-questions@freebsd.org mailing list http://lists.freebsd.org/mailman/listinfo/freebsd-questions To unsubscribe, send any mail to "freebsd-questions-unsubscr...@freebsd.org"