From: Loyd <loydlin@aol.com>
To: Teacher2Teacher Public Discussion
Date: 2002101020:37:00
Subject: Re: Use of Percentage Sign in equation

On 2002101012:34:04, William wrote:
>	
>I was asked by a mother whether a percentage cane be represented in
an
>equation like the following. 
>
>
>The example here asks:
>
>"A shop keept sells 20% of his orange stock today @ $0.5 each and he
>earns $50 today. So how many orange he has in stock when he start
>business?"
>
>I was asked whether this is an appropriate formau:
>
>Say y is the original number of oranges
>
>20%y * 0.5 = 50.
>
>I was doubt that notation like "20 % y" means something else in
>mathematic world...where the "%" is an operators of special use. 
>
>Please help.
>
% means divide by 100, so 20% = .20  (that is 20/100).  Also, Per
means divide so, "percent" means divide by a hundred. 

Let y= original number of oranges.

(.2y)*.5 = 50
.1y = 50
 y= 500 oranges. 

Your equation gives the same thing.  
20%y * 0.5 = 50
10%y = 50
y = 500 (10% of 500 = 50

The usual procedure is to change the percent to a decimal.

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