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Percentages
Percentages, like fractions and decimals, represent a portion of the whole and are heavily tested on the exam in
a number of ways. Percentages are based on the whole of 100. 20% of something is essentially 20 parts of 100. 
Percentages can be written a number of different ways. For example, we can write 20% as follows:
20% or 20 
_ 
100 or .20
On the exam, you may be asked to calculate what percentage an integer is of another integer. For example, a problem
solving question may ask you:
5 is what percentage of 20?
5 = ?%(20) 
Write the problem as an equation
5 =
x
_ 
100 (20) 
Since percentages are always based on 100, you can add more information to the
equation to help you solve and substitute an unknown variable for the value we
are missing.
5 = 20 
x
_

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100 = 2 
x
_
10 =
x
_5
Reduce the fraction
5 =
x
_5
Cross-multiply
25 =
x 
5 is 
25
% of 20
You solved the problem and got the correct answer, but it took a lot of steps, which translates to a lot of time. There
are some common formulas you can use on the exam to help approach percentage problems of various types. Let us
look at these in more detail.
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ARGOPREP.COM/GRE
Part of the Whole Formula
Problems involving percentages on the exam will normally, like the previous problem, give you two of the values and
ask you to calculate the third. In the previous example, you had 5, the part, and 20, the whole. You were looking for
the percentage. You can solve the problem with fewer steps by using a formula:

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