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Calculate Percent - GMAT and GRE Math Answers and Explanations

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Are you preparing for the GRE or the GMAT? If these timed graduate and business school exams are in your future, here's a short cut for answering percent questions. More specifically, this article focuses on how to easily calculate the percentage of a number.

Suppose a question required you to find 40% of 125. Follow these simple steps.

Four Steps to Calculate a Percentage

Step 1: Memorize these percents and their corresponding fractions.

  • 100% = 1
  • 50% = 1/2
  • 25% = 1/4
  • 33 1/3% = 1/3
  • 20% = 1/5
  • 10% = 1/10


Step 2: Choose a percent from the list that fits with the percent in question. For example, if you are looking for 30% of a number, choose 10% (because 10% * 3 = 30%).

In another example, a question requires you to find 40% of 125. Choose 20% since it is half of 40%.

Step 3: Divide the number by the denominator of the fraction.

Since you've memorized that 20% is 1/5, divide 125 by 5.

125/5 = 25

20% of 125 = 25

Step 4: Scale to the actual percent. If you double 20%, then you'll reach 40%.  Therefore, if you double 25, you'll find 40% of 125.

25 * 2 = 50

40% of 125 = 50

Answers and Explanations

Original Worksheet

1. What is 100% of 63?
63/1 = 63

2. What is 50% of 1296?
1296/2 = 648

3. What is 25% of 192?
192/4 = 48

4. What is 33 1/3% of 810?
810/3 = 270

5. What is 20% of 575?
575/5 = 115

6. What is 10% of 740?
740/10 = 74

7. What is 200% of 63?
63/1 = 63
63 * 2 = 126

8. What is 150% of 1296?
1296/2= 648
648 * 3 = 1944

9. What is 75% of 192?
192/4 = 48
48 * 3 = 144

10. What is 66 2/3% of 810?
810/3 = 270
270* 2 = 540

11. What is 40% of 575?
575/5 = 115
115 * 2 = 230

12.  What is 60% of 575?
575/5 = 115
115 * 3 = 345

13. What is 5% of 740?
740/10 = 74
74/2 = 37

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