Yes. "percent greater than/less than" is always about how much more/less than the original number. "Percent of" is about how much of the original number.

30%

of 10 = .3(10) = 3

80%

of 5 = .8(5) = 4

30%

greater than 10 = 10 + .3(10) = 10 + 3 = 13

80%

less than 5 = 5 - .8(5) = 5 - 1 = 4

Now, for these latter problems (% greater/less than), we don't have to use addition/subtraction as above. We can add 1 or subtract from 1:

30%

greater than 10 = (1+.3) * 10 = 1.3(10) = 13

80%

less than 5 = (1-.8) * 5 = .2(5) = 1

This gets the same result, but it can be a little quicker. We can even use it if we have a variable:

x% less than 50 is 35. What is x?

Here, we can represent "x%" as "x/100."

50 - (x/100)(50) = 35

(50)(1 - x/100) = 35 (With practice, you might see this second step directly and not write the first version.)

(1 - x/100) = 35/50 = 7/10

1 - 7/10 = x/100

3/10 = x/100

300 = 10x

30 = x

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Dmitry Farber | Manhattan GMAT Instructor | New York

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