Percentages in Algebra

Date: 12/29/95 at 0:55:34
From: Christine M Moss
Subject: Simple algebra

What number increased by 30% = 260?  
I know the answer, but how did I get it?

Thank you.

Date: 1/3/96 at 17:0:0
From: Doctor Elise
Subject: Re: Simple algebra

Hi!

Increasing a number by 30% is the same as adding 30% of
the number to 100% of the number.  If we call the number
'y', then the actual math problem becomes:

100% of y plus 30% of y = 260

In math problems, 'of' means multiplication, and percentages
have to be converted into decimals, so we have

(1.00 * y) + (.30 * y) = 260

(1.00 + .30) * y = 260

1.30 * y = 260

y = 260/1.3

Does this help?

-Doctor Elise,  The Math Forum