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# What is the difference between percentage change, and...

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Intern
Joined: 21 Feb 2012
Posts: 1
What is the difference between percentage change, and...  [#permalink]

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27 Feb 2012, 23:02
I understand the formula for percentage change is:

end value - start value/ start value = x% or percentage change.

and percentage of is

x * x%/100 = z

i.e.

10 x 100/100 = 10%

however you can use percentage of to calculate percentage change, like this:

ex 1.

percentage change:

60-50/50 * 100 = 20%

Using percentage of:

50 x y% = 60

y = 60/50*100 = 120

I can't seem to understand why you would use one over the other, when you can get the same result using either.

Cheers

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Intern
Joined: 03 Feb 2012
Posts: 46
Location: United States (WI)
Concentration: Other
Schools: University of Wisconsin (Madison) - Class of 2014
GMAT 1: 680 Q46 V38
GMAT 2: 760 Q48 V46
GPA: 3.66
WE: Marketing (Manufacturing)
Re: What is the difference between percentage change, and...  [#permalink]

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28 Feb 2012, 20:33
On the GMAT it seemed to me very obvious when to use any of the percentage-based formulas - the question itself was the indicator. I do not recall ever really having to make any assumptions or guesses between the two options.

If you are asking in more general terms (i.e. what is the practical application of each?) - I prefer percentage change in sales reporting as it is generally easier for others to grasp. I have yet to come across a practical use for percentage of with the exception of seeing it used to make a change or difference seem larger (e.g. would you rather report a 5% increase in sales or sales being at 105% of last period? anyone paying attention would see through the tactic but some may miss it). I don't use percentage of pretty much as a rule.
Veritas Prep GMAT Instructor
Joined: 16 Oct 2010
Posts: 9701
Location: Pune, India
Re: What is the difference between percentage change, and...  [#permalink]

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29 Feb 2012, 05:33
2
theknighht wrote:
I understand the formula for percentage change is:

end value - start value/ start value = x% or percentage change.

and percentage of is

x * x%/100 = z

i.e.

10 x 100/100 = 10%

however you can use percentage of to calculate percentage change, like this:

ex 1.

percentage change:

60-50/50 * 100 = 20%

Using percentage of:

50 x y% = 60

y = 60/50*100 = 120

I can't seem to understand why you would use one over the other, when you can get the same result using either.

Cheers

When a value increases/decreases and you know both the original and the final values, you find the percentage change.
Say your score was 500 and now it is 600. The percentage change is (600 - 500)/500 * 100 = 20%

'percentage of' is used in many situations e.g. You might have the initial value and percentage increase/decrease. You need to find the final value.
Your GMAT score has increased by 20%. Your first GMAT score was 500. What is the 20% of 500?
(20/100) * 500 = 100
So your new GMAT score must be 500 + 100 = 600 (final value)

Another example for 'percentage of'
There are total 120 students in a class. Out of these, 48 are boys. What 'percentage of' students are boys?
We need to find this - 48 is what percentage of 120? Say 48 is x% of 120.
120 * x/100 = 48
x = 40%
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Karishma
Veritas Prep GMAT Instructor

Non-Human User
Joined: 09 Sep 2013
Posts: 13162
Re: What is the difference between percentage change, and...  [#permalink]

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14 Mar 2018, 17:07
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This discussion does not meet community quality standards. It has been retired.

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To review the GMAT Club's Forums Posting Guidelines, please follow these links: Quantitative | Verbal Please note - we may remove posts that do not follow our posting guidelines. Thank you.

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Re: What is the difference between percentage change, and...   [#permalink] 14 Mar 2018, 17:07
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