Associated Topics || Dr. Math Home || Search Dr. Math

### Finding Percentage of Increase

```Date: 06/07/2003 at 23:03:06
From: Chief
Subject: Percentage increase

Find the percentage increase: old, \$50.50; new \$75.75.
```

```
Date: 06/08/2003 at 01:28:55
From: Doctor Mike
Subject: Re: Percentage increase

Hello,

You first figure out the amount of increase. That is 75.75 minus
50.50, which is 25.25.

When you deal with percentages, you compare the increase with the
original, which in your case is 50.50.  (original = old)

For me, it has always been easier to understand this comparison step
by putting it in terms of a fraction before doing the percentage
version of the answer. The fraction is

increase
----------
before

For this problem, the numbers for it are

25.25
-------
50.50

This turns out to be exactly 0.5 or 1/2.

Finally, the percentage is the fraction multiplied by 100.  100 times
0.5 is 50, so the answer is 50 percent.

Put into words, it is a 50 percent increase to go from 50.50 to 75.75.

Here is a similar problem where the numbers involved are easier. You
should do the work to convince yourself that it is also a 50% increase
to go from 50 to 75.  You are adding 25 (half of 50 = 50 percent of
50) to get from 50 to 75. See? Good!

Here is another useful related example. If you go from 50 to 100 you
double the amount. That is, you add 100% of the original to get the
new. This is a 100% increase.

- Doctor Mike, The Math Forum
http://mathforum.org/dr.math/

```
Associated Topics:
Middle School Fractions

Search the Dr. Math Library:

 Find items containing (put spaces between keywords):   Click only once for faster results: [ Choose "whole words" when searching for a word like age.] all keywords, in any order at least one, that exact phrase parts of words whole words

Submit your own question to Dr. Math
Math Forum Home || Math Library || Quick Reference || Math Forum Search