# GRE Quantitative Comparison: Strategy, Examples | topin

GRE guidesQuantitative Comparison

Section

Quantitative Reasoning, grouped at the start of each section

Answer choices

Always the same four: A greater, B greater, equal, cannot be determined

Count

Several in each Quant section

Time

Quant averages under two minutes a question; many QCs take one

Calculator

Available, but most QCs are faster with reasoning

## How it works

You see Quantity A and Quantity B, sometimes with centred information above them that applies to both. You choose A if Quantity A is always greater, B if Quantity B is always greater, C if they are always equal, and D if the relationship depends on values the information does not fix. A, B or C must hold for every possible case; a single counterexample rules them out.

## Worked example

x is a nonzero number and -1 < x < 1\. Quantity A: x^2 Quantity B: x

1. AQuantity A is greater.
2. BQuantity B is greater.
3. CThe two quantities are equal.
4. DThe relationship cannot be determined from the information given.
Show the answer

The relationship cannot be determined from the information given.

Try a positive value: x = 0.5 gives Quantity A = 0.25 and Quantity B = 0.5, so B is greater. Try a negative value: x = -0.5 gives Quantity A = 0.25 and Quantity B = -0.5, so A is greater. Two allowed values give different results, so the answer is D. Anyone who only tries a positive fraction picks B, and anyone who assumes squaring makes numbers bigger picks A.

## A method for Quantitative Comparison

1. 1  
### Read the centred information first  
Note every condition: is the variable an integer, positive, nonzero, within a range? Anything not stated is allowed, including zero, negatives and fractions.
2. 2  
### Simplify both quantities together  
Treat the comparison like an equation: add, subtract or cancel the same term on both sides. Multiply or divide both sides only by a positive number, because a negative flips the relationship.
3. 3  
### Compare without full calculation  
You only need to know which side is bigger, not by how much. Estimate, compare parts piece by piece or rewrite both sides in the same form.
4. 4  
### Test different kinds of numbers  
When variables are involved, try a positive integer, zero, a negative, a fraction between 0 and 1 and a large number, as far as the conditions allow. Stop as soon as two values give different relationships.
5. 5  
### Rule out D before choosing A, B or C  
If every case you try gives the same result, ask whether a value you have not tried could change it. Only then commit to A, B or C.

## Traps to avoid

* Assuming a variable is a positive integer when the question does not say so.
* Multiplying or dividing both quantities by a variable whose sign is unknown.
* Trusting a figure's proportions when it is not drawn to scale.
* Choosing C because both quantities look alike, without checking that they are equal for every value.
* Choosing D for any question with a variable, when a variable can still give a fixed relationship.

## Quantitative Comparison FAQs

What are the answer choices in GRE Quantitative Comparison?

Always the same four: Quantity A is greater; Quantity B is greater; the two quantities are equal; the relationship cannot be determined from the information given.

Can the answer be D if there are no variables?

No. If both quantities are fixed numbers, one is greater or they are equal, so the answer is A, B or C.

How many Quantitative Comparison questions are on the GRE?

The exact number varies, but each Quant section opens with several, and they make up a large share of the measure.

How do I get faster at Quantitative Comparison?

Learn to simplify both sides and pick test numbers by habit. Practising topin's Quantitative Comparison sets under a timer shows which number types you forget to try.

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