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percent of formula
is/ of formula
​What is a "percent of" problem. Here are two examples.
What is 20 percent of 500? 

You recently got a raise at work and your salary increased from $400 to 445. What is the percent of increase?

 Follow these steps to solve " percent of " problems.

Step 1. Use the formula:

​Step 2. Plug in the correct numbers in the formula by looking for context clues.

Step 3. Solve for x by completing a cross product.

Let's look at an example:

12 is what percent of 8?


Step 1. Use the formula:   





Step 2. 





Step 3. ​ Solve for x by completing a cross product  8x =1200

Step 4. Divide both sides by 8 so    x=150%


video tutorial percent of
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Percent of a number

The phase " is" is replaced by 12
The phase "of " is replaced by 8
The percent becomes your variable so it becomes the x
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Percent Increase

Proportion word problems
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Use the percentage calculator to check your work

Percentage Word Problems

Thirty students took a Math test. If only five of these students passed the test, what percent failed?
Drew received an 80% on his EOCT Math test. The test had 200 questions on it. How many questions did Drew get incorrect?
Thirty students attend a Math class. Twenty of those students are female. 
What percent of the class are female?

Kate bought a new dress at 85% of the regular price. 
After the discount of 85% she paid $20.00 for the dress. What was the regular price?  

Video answer to the Percentage Word problems
If 5 passed 25 failed
Place part/whole  25/30 = .83 
.83 x 100 = 83%

 He missed 20% of the questions therefore, 20% of 200 = number of incorrect answers
.20 x200 =40
He missed 40 questions

The class has 20 females and 10 males
Place  part/whole  20/30 = .66
.66 x 100 = 66%

Original price x .85 = 20
Divide each side by .85

Original price x .85  = 20    
​                .85                  .85
= $ 23.53
Transcript Percent of Problems Hi Welcome to MooMooMath. Today we are going to talk about percent of problems, and you will often see these as word problems. For example,what is 20 percent of 500? I will write my formula, is over of equals percent over 100. Now let's plug in some numbers : “what is” equals x, “of” is 500, and "percent" is twenty over 100. Next, I cross multiply, divide both sides by 100 and x is 10. OK what rule did I use to solve this problem? Once you get the rule down it’s really pretty easy. So the rule is simply this. Remember the formula, is over of ,is equal to the proportion (percent) over 100. So what you have to identify is “Where is my variable?” Is it the, is, of, or the percentage? So let’s look at the second example. OK I’m going to write the formula, is over of ,equals percentages, over 100. Now let’s do some replacing here. I will replace " is" with 12 “ what percent” I don’t know my percentage so I will replace that with x of 8. Now let’s do a cross product, 8 times X equals 8x, 12 times 100 is 1200 and I will divide both sides by 1200 and so 8 goes into 1200 ( 1200 divided by 8 equals 150) so I end up with 150. So that means 12 is 150 percent of 8 If you stick with the "is over of" and "percent over 100" you will get it right every time. Hope this was helpful.