[math-fun] hiſtorical myſtery
R. Weyhrauch notes that http://digital.library.pitt.edu/cgi-bin/t/text/pageviewer-idx?c=darltext;cc=... (a document older than the dollarsign) prescribes a bunch of tariffs in 90ths instead of %. I thought I had a mathematical motivation, but was wrong. NeilB thought of a historical, rather than mathematical explanation, but it seems decreasingly plausible. Can someone at least provide a good guess? --rwg
Total off-the-wall guess: In old financial conventions, some of which persist to this day, a year is reckoned as 360 days (which I guess simplified the arithmetic), and so one quarter of a year is 90 days. --Dan On Apr 23, 2014, at 3:13 PM, Bill Gosper <billgosper@gmail.com> wrote:
R. Weyhrauch notes that http://digital.library.pitt.edu/cgi-bin/t/text/pageviewer-idx?c=darltext;cc=... (a document older than the dollarsign) prescribes a bunch of tariffs in 90ths instead of %. I thought I had a mathematical motivation, but was wrong. NeilB thought of a historical, rather than mathematical explanation, but it seems decreasingly plausible.
Can someone at least provide a good guess?
http://tywkiwdbi.blogspot.com/2012/11/thirty-nine-ninetieths-of-dollar.html On Wed, Apr 23, 2014 at 4:23 PM, Dan Asimov <dasimov@earthlink.net> wrote:
Total off-the-wall guess: In old financial conventions, some of which persist to this day, a year is reckoned as 360 days (which I guess simplified the arithmetic), and so one quarter of a year is 90 days.
--Dan
On Apr 23, 2014, at 3:13 PM, Bill Gosper <billgosper@gmail.com> wrote:
R. Weyhrauch notes that http://digital.library.pitt.edu/cgi-bin/t/text/pageviewer-idx?c=darltext;cc=... (a document older than the dollarsign) prescribes a bunch of tariffs in 90ths instead of %. I thought I had a mathematical motivation, but was wrong. NeilB thought of a historical, rather than mathematical explanation, but it seems decreasingly plausible.
Can someone at least provide a good guess?
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-- Mike Stay - metaweta@gmail.com http://www.cs.auckland.ac.nz/~mike http://reperiendi.wordpress.com
Makes it easier for pi charts? On 2014-04-23 18:13, Bill Gosper wrote:
R. Weyhrauch notes that http://digital.library.pitt.edu/cgi-bin/t/text/pageviewer-idx?c=darltext;cc=... (a document older than the dollarsign) prescribes a bunch of tariffs in 90ths instead of %. I thought I had a mathematical motivation, but was wrong. NeilB thought of a historical, rather than mathematical explanation, but it seems decreasingly plausible.
Can someone at least provide a good guess? --rwg _______________________________________________ math-fun mailing list math-fun@mailman.xmission.com http://mailman.xmission.com/cgi-bin/mailman/listinfo/math-fun
participants (4)
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Bill Gosper -
Dan Asimov -
Mike Speciner -
Mike Stay