Drexel dragonThe Math ForumDonate to the Math Forum



Search All of the Math Forum:

Views expressed in these public forums are not endorsed by Drexel University or The Math Forum.


Math Forum » Discussions » Inactive » k12.ed.math

Topic: Converting pesos to dollars and vs versa
Replies: 3   Last Post: Jul 27, 2005 1:22 AM

Advanced Search

Back to Topic List Back to Topic List Jump to Tree View Jump to Tree View   Messages: [ Previous | Next ]
Kevin Karplus

Posts: 190
Registered: 12/6/04
Re: Converting pesos to dollars and vs versa
Posted: Jul 27, 2005 1:22 AM
  Click to see the message monospaced in plain text Plain Text   Click to reply to this topic Reply


On 2005-07-27, DanielLee <dlh3648@yahoo.com> wrote:
> $1,000 usd @ 10.683 = $10,682.750 pesos
>
> When I am converting pesos to dollars the exchange rate is shown like
> this
>
> $10,682 pesos @ 0.09361 = $999.92980 dollars
>
> I know that the exchange rate may be different for each conversion
> depending on currency values or what ever. I was figuring that the
> dollar to peso number of 10.683 could lead me to the number I needed if
> I wanted to convert pesos to dollars at the same rate.
>
> It seems that since a dollar to peso rate of 10.000 is equal to a pesos
> to dollar rate of 0.10000. Or stated another way (10 before the decimal
> point was equal to 10 after the decimal point) then a 10.5000 number
> before the decimal point would equal a .09500 (or some such number)
> after the decimal point. That the addition to one would equal the
> subtraction from the other. But when I do it that way it does not work.


Indeed it does not. 1/10.5 is approximately 0.95238 (more precisely,
it is 0.95238095238095238...).


> What I would like to know now is how do I do the math to get the
> inverse number?


The multiplicative inverse of a number is 1 divided by the number.
(Technically, this statement is a bit backward, as division is defined
as multiplication by the multiplicative inverse, but the basic idea,
that multiplying a number by its multiplicative inverse gives you 1,
is the key point.)

So if you have 10.5 pesos per dollar, you have 1/10.5 dollars per peso.

You really only need one exchange rate (if there is no markup or
commission being computed). You then multiply by the exchange rate to
do the conversion in one direction, and divide by it to do the
conversion in the other direction.

$1000 * 10.5 pesos/dollar = 10,500 pesos

10,500 pesos / 10.5 pesos/dollar = $1000

------------------------------------------------------------
Kevin Karplus karplus@soe.ucsc.edu http://www.soe.ucsc.edu/~karplus
Professor of Biomolecular Engineering, University of California, Santa Cruz
Undergraduate and Graduate Director, Bioinformatics
(Senior member, IEEE) (Board of Directors, ISCB)
life member (LAB, Adventure Cycling, American Youth Hostels)
Effective Cycling Instructor #218-ck (lapsed)
Affiliations for identification only.


--
submissions: post to k12.ed.math or e-mail to k12math@k12groups.org
private e-mail to the k12.ed.math moderator: kem-moderator@k12groups.org
newsgroup website: http://www.thinkspot.net/k12math/
newsgroup charter: http://www.thinkspot.net/k12math/charter.html




Point your RSS reader here for a feed of the latest messages in this topic.

[Privacy Policy] [Terms of Use]

© Drexel University 1994-2014. All Rights Reserved.
The Math Forum is a research and educational enterprise of the Drexel University School of Education.