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  • GRE Quant Strategy: Pick Nice Numbers

    GRE Quant Strategy: Pick Nice Numbers
    Monday, May 20, 2019

    The GRE is a standardised test used to test the candidates’ aptitude for graduate programmes including STEM (Science, Technology, Engineering & Mathematics), management programmes in the United States and other universities around the world. while GRE indeed tests your verbal, quantitative and writing skills, its main objective is to assess your analytical and logical capabilities – a necessity for all graduate Masters / Doctoral programmes. Thus, all the sections of the test are designed to challenge you on these skills. The test always begins with the analytical writing tasks, followed by the verbal, quantitative and unscored sections that may appear in any order.

    The GRE is a computer-based test (CBT). The test is sectional adaptive, which means that the performance on the first quantitative section shall determine the level of questions in the second quantitative section. However, within each section, the questions are non-adaptive, and you can scroll back and forth. The first section shall try to assess your mathematical aptitude at a broad level. The second quantitative section shall try to accurately determine your Quantitative aptitude on a scale of 130 to 170.

    The objective of the verbal section is to measure your ability to read and understand written English passages, to evaluate reasoning arguments, analyse relationships among words and concepts, and relationship among component parts of sentences. GRE tests skills to solve a question in the most efficient manner. When algebraic questions require complex equation with variables, then picking Nice Numbers is a good strategy.

    What is Nice Numbers Strategy?

    The numbers that are easy to replace variables generally in algebraic questions are Nice numbers. The choice of these numbers depends on the question type and information given along.

    When to use this technique?

    Arithmetic operations such as addition, subtraction, multiplication and division on real numbers are much easier than solving for variables using equations.

    This technique can be applied:

    • When the question talks about a number but only supplies a variable, generally in algebraic questions

    • When questions are related to percentage, ratio or proportion topic

    • When the question appears hard to understand, then also you can use this technique. For easier question you may use generic way of solving the question. Let’s understand this with the help of an example:

    If m machines are filling oil at the rate of 5 litres per machine per hour. How many litres of oil can be filled in 7 hours?

    A) 5m              B) 7m              C) 35m                        D) 60m

    When m=2 in the above question, it will look like this:

    If 2 machines are filling oil at the rate of 5 litres per machine per hour. How many litres of oil can be filled in 7 hours?

    No matter how good you are in algebra, it’s still easier to work with real numbers. How to apply the technique? Here is how to solve the question using this technique:

    Identify the question: When question refers to a number but only supplies a variable for that number, then pick Nice Number to replace the variable. Pick a Nice number to replace the variables: You need to pick the number as the constraints given in the question. Generally, 2 or 3 is a good choice to replace variable in algebraic questions. Find the target by Solving the question using the Nice number: When n=2, then solve the question arithmetically and find your target answer. Match the Target: Plug in your Nice Number in the option choices and see which option matches the target.

    Let’s apply the technique to previous question:

    If m machines are filling oil at the rate of 5 litres per machine per hour. How many litres of oil can be filled in 7 hours? Pick a Nice number: When m=2.

    If 2 machines are filling oil at the rate of 5 litres per machine per hour. How many litres of oil can be filled in 7 hours?

    Find the target:

    Total 10 litres of oil are filled in one hour by the two machines at the given rate. So, in 7 hours total 70 litres of oil is filled. Target answer is 70.

    Match the Target:

    A) 5 X 2 = 10                Incorrect

    B) 7 X 2 = 14                Incorrect

    C) 35 X 2 = 70 This matches our target!

    D) 60 X 2 = 120           Incorrect

    Hence (C) is correct answer.

    Which is better: Nice Numbers technique OR Algebraic Approach. Let’s solve the next question with the help of Nice numbers and by using algebraic approach.

    A departmental store buys 5 trousers for T dollars and sells each of them at a profit of 20% of the original value. In terms of T, what is the selling price of each trouser?

    A) T/5

    B) 6T/5

    C) 6T/25

    D) 100T

    E) 100/T

    Pick Nice Number:

    To calculate price of each trouser T is divided by 5. So, lets pick Nice number T=10, then the store buys 5 trousers for 10 dollars. So, price of each trouser is $2.

    Find the target:         

    If the price of each trouser is increased by 20% of the original, then the selling price is 1.20 of the original value            = 1.20 X 2 = 2.4 dollars becomes target value.

    Match the target

    Plug Nice number T=10 in answer choice and find the match with target

    A) 10/4 = 2.5               Not correct

    B) 6 X 10 /5 = 12         Not correct

    C) 6 X 10/25 = 2.4       Correct!

    D) 100 X10 = 1000      Not correct

    E) 100/10 = 10            Not correct

    Correct answer is (C).

    Let’s apply algebraic approach now:

    If a store buys 5 trousers for T dollars, then cost price of each trouser is T/5. Price of each trouser is increased by 20%, so the selling price is 120% of the original value = 1.20 X (T/50) = (6/5) X (T/50) = 6T/25. Option (C) is correct.

    Though algebraic method may seem to be easier, chances of mistakes in this method are high. As mentioned earlier, if the question is easy and can be solved with the equations, then solve the question with the algebraic approach. But when the question is difficult, try to solve it by picking Nice numbers.

    Things to remember: Nice Numbers

    • Pick the numbers that are easy to work as per the question.

    • Do not generally pick 0 or 1 as they have unique characteristics.

    • Avoid picking numbers that have already appeared in the question statement and options.

    • Remember about the constraints according to the question. If the condition says x>2, then pick x=3. Generally, 2 and 3 are considered good options for picking nice numbers for algebraic questions and 100 for percentage questions.

    • When multiple numbers are to be picked, then the numbers having different characteristics can be chosen e.g.: co-primes, odd and even, etc.

    Important:
    The only way to feel confident with this technique is practice! The more you practice, the better you are! It is suggested that during practice sessions the questions should be solved with both the methods i.e. by the algebraic approach as well as by picking Nice Numbers. Use this strategy wisely and save them for the time when you need it most!

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