The quantitative reasoning section of the GMAT exam allows individuals to test their logical, critical and quantitative problem-solving skills that are vital in the world of business and management. Percentage is a fundamental principle of mathematics used in our daily lives. You use percentage when you’re calculating your marks, discount on your favorite shoes, profit achieved by your company or even the percentage of the battery in your iPhone. Here is all the information that you need to know how to nail percentage questions for GMAT.
Percentage Questions: Understanding the Concept
Percentage means per hundred which is conceptualized to describe parts of a ‘whole.’ The symbol used for percentage is ‘%’.
Formula: Part/Whole * 100
E.g. 25% of 600 is (25/100) * 600 = 150
A Comprehensive Guide to Percentage Questions
GMAT percentage problems under quantitative reasoning are mainly concerned with calculating percentage change. Percentage change is the difference in the percentage between a starting and an ending number.
Percent Change = ( Amount of Change/Starting Amount) * 100
Example: Suppose the price of a refurbished car changes from $2,000 to $ 2,500 and you have to calculate the percent increase.
Amount of change = $2,500 – $2,000 = $500
Starting amount = $2,000
Percent change = (500/2000) * 100 = 25%
Further, percentage questions can also come in the form of arithmetic and geometry problems.
Example: If the length of the sides of the square is increased by 10%, by how much percent will its total area increase?
You will also find percentage questions related to calculations of profit or percent change in the interest of a bank account.
Also Read: GMAT Profit and Loss Questions
Percentage Questions: Tips and Tricks
GMAT percentage problems can be quite tricky. To score well in this section, it is crucial to have clarity about percentage concepts and answer those questions in a timed manner. Below are some important tips to keep in mind while solving percentage questions:
Percentage Questions: Read in Between the Lines
Some complex questions can cause confusion and result in selecting the wrong option. That’s why it is important to read the questions carefully.
Example: A video camera costs $500 and its price suddenly doubles. Now, the cost of the video camera is $1000. $1000 represents an increase of 100% from the original price of the video camera, but 200% of the original cost of the video camera.
Whether you’re calculating the percent change or the proportion of the original cost of the video camera you’ll have to look for two different numbers.
Percentage Questions: Sense the Increase-Decrease or Decrease-Increase Trap
First, take a look at the example below:
Example: The price of pumpkins increased by 40% and then decreased by 40%. Calculate how much percent the final price is of the original price?
In a question like this, it is common to think that the answer is 100% because the price of the pumpkin has increased and decreased by the same percent change. However, when you increase an amount by some percent and then decrease it by the same percent you do not get the amount that you started with.
In short, if the price of pumpkins is increasing by 40% use the new price as a starting value to solve the question further. To calculate the final answer, you’ll have to multiply the two multipliers, which we will get to learn in the next section.
Percentage Questions: Multiply the Multipliers
Let’s continue with the above example.
The price of pumpkin is initially increased by 40%. The multiplier used for the increase is 1.4.
The price of pumpkin then falls by 40%. Then, the decrease is 0.6.
To calculate the total change, we will multiply the multipliers.
1.4 * 0.6 = 0.84
Therefore, the final price of the pumpkin is 84% of the initial price, which means the price got decreased by 16%.
If you have more than one multiplier, multiply the multipliers to calculate the actual percent change.
Percentage Questions: Identify the Starting Value
It is important to ensure that you correctly identified the starting value while calculating percent change.
For example, the price of an oven is now $300, having decreased from $400.
Read the statement carefully because $400 is put in the next line to make it confusing. Here, the starting value is $400.
Percentage Questions: Knowing your Multipliers
There are three most important multipliers that you’ll come across while practicing the percentage questions for GMAT. It is pivotal to understand which one to use in order to solve a percentage problem.
X% of a Number
You can find X% of a number by multiplying the number by the percent in decimal.
Let’s say you’re trying to calculate 75% of 200. In order to do this, multiply 200 by 75% to find the correct percentage.
0.75 * 200 = X
Therefore, the formula for finding X% of a number is:
Percent in decimal * Original value
To calculate an increase in value, multiply the increase multiplier by the original value.
Example: Suppose the money in your savings account increases 20% over the year from its original value of $1000.
Percent increase = 1.2 * 1000 = X
Here, we used 1.2 because to find the multiplier of a percent increase question, we add 1 to the percentage in decimal.
Increase multiplier = 1 + (percent in decimal)
1 + 20% = 1 + 0.2 = 1.2
To calculate a decrease in value, multiply the decrease multiplier by the original value.
Example: Say the money in your savings account decreased by 20% over the year from its original value of $100.
Percent decrease = 0.8 * 1000 = X
Here, we used 0.8 because to find the multiplier of a percent decrease problem we subtract the percent decrease from 1.
Decrease multiplier = 1 – (percent as a decimal)
1 – 20% = 1 – 0.2 = 0.8
Also Read: GMAT Paper Pattern – Latest 2020 Update
Percentage Questions for GMAT: Things to Remember
- Consistent practice can help you in mastering the quantitative reasoning section of the GMAT.
- Understand the central concepts of percentage thoroughly.
- Train yourself to solve questions in a timed manner.
- Pen down your doubts and if needed, take help from experts of mathematics.
Also Read: Importance of Reading
We understand that preparing for the GMAT can be a stressful process but with the help of the experts at Leverage Edu you can come up with a plan to tackle these challenges so that nothing comes between you and your dream college.