## Working with Percents

Summary
Mastering the use of percents in GRE problems involves understanding percents as multipliers, translating percentage problems into mathematical equations, and utilizing fractions for certain percentages.
• Percents can be converted into multipliers by changing them into their decimal form to easily calculate a percentage of a number.
• To solve for an unknown in percentage problems, replace the unknown with a variable and translate the problem into an equation using the percent as a multiplier.
• When finding what percent one number is of another, set up an equation with the unknown percent as a variable, solve, and remember to convert the decimal back to a percentage.
• For percentages that are easily represented as fractions (e.g., 50%, 25%), it can be simpler to convert the percent to a fraction to solve the problem.
• Practice problems are provided to apply these strategies and reinforce understanding.
Chapters
00:21
Percents as Multipliers
01:17
Solving for an Unknown
01:41
Finding the Percent
02:15
Percents and Fractions

Solutions to the Practice Problems:

1) What is 60% of 60

Let's translate this into a simple equation.

What --> "x" or what we are trying to find.

is --> "="

60% --> 60/100 or .6

of --> " *"

x = .6 * 60

x = 36

So all we did was multiply 0.6*60 and we get 36 as our answer.

2) 52 is 40% of what number?

is --> "="

40% --. 40/100 or .4

of --> " * "

what number --> x

52 = .4 * x

We divide both sides by 0.4 and we get X = 52/0.4 = 130

Let's do a check and make sure we did everything right.

3) 18 is what percent of 45?

Before we do anything math let's do a ball park. We know that half of 45 is 22.5 So without doing any math/computation we know that 50% of 45 is 22.5 so 18 is going to be less than 50>#/p###

is --> " ="

what percent --> x/100

of --> "*"

18 = (x/100) * 45

18/45 = x/100

.4 = x/100

40 = x

So 18 is 40% of 45.

Notice we can simply divide 18 by 45 to get .4

.4 is 40% in decimal form.

4) What is 50% of 128? [64]

This one you're just dividing 128 by 2.

x = .5 * 128 or 128/2

128/2 = 64