All GRE Math Resources
Example Questions
Example Question #1 : How To Evaluate Algebraic Expressions
Quantitative Comparison
0 < x < 1
A
---
(2x + 5)/(x2)
B
---
5x
Quantity A is greater
The relationship cannot be determined from the information given
Quantity B is greater
The two quantities are equal
Quantity A is greater
Since A is a fraction with an exponential term in the denominator, its maximum value is when x is at a minimum. In B, the maximum value is when x approaches its maximum. Therefore, we can check whether there is overlap between the two quantities: No matter how close to either 0 or 1 x reaches, A will always be greater than B. (In fact, the minimum value for A is ~7, while the maximum value of B is ~5)
Be sure to keep your value of x consistent when plugging between the two fractions! The question asks for when they have the same x-value, not for when they are solved independently.
Example Question #2 : Evaluating Expressions
If x = -4 and y = 7, what is the value of 3x-5y?
Substitute the values into equation: 3(-4) - 5(7) = -12 - 35 = -47.
Example Question #3 : Evaluating Expressions
Quantitative Comparison
Quantity A: x
Quantity B: 2x
Quantity B is greater.
The relationship cannot be determined from the information given.
The two quantities are equal.
Quantity A is greater.
The relationship cannot be determined from the information given.
For a quantitative comparison question such as this one, it is best to first plug in the numbers 0, 1, and –1. Plugging in 0 gets the same answer for both columns. Plugging in 1 makes Quantity B bigger. Plugging in –1 makes Quantity A bigger. Therefore the answer cannot be determined.
Example Question #2 : How To Evaluate Algebraic Expressions
A store sells 17 coffee mugs for $169. Some of the mugs are $12 each and some are $7 each. How many $7 coffee mugs were sold?
7
6
10
9
8
7
The answer is 7.
Write two independent equations that represent the problem.
x + y = 17 and 12x + 7y = 169
If we solve the first equation for x, we get x = 17 – y and we can plug this into the second equation.
12(17 – y) + 7y = 169
204 – 12y + 7y =169
–5y = –35
y = 7
Example Question #3 : How To Evaluate Algebraic Expressions
Kim has 22 coins made up of quarters, nickles, and dimes that total $2.45. Kim has twice as many nickles as quarters. How many dimes does she have?
Cannot be determined
7
10
5
12
7
The answer is 7.
Let us first write down three equations that represent the problem:
n + d + q = 22
2q = n
5n + 10d + 25q = 245
Lets plug the second equation into the first and third equations:
(2q) + d + q = 22
5(2q) + 10d + 25q = 245
Solve the first equation for d and plug into the last equation:
d = 22 – 3q
10q + 10(22 – 3q) + 25q = 245
Solve for q.
220 – 30q + 25q + 10q = 245
5q = 25
q = 5
Therefore, n = 10 and d = 7
Example Question #6 : Evaluating Expressions
In the equation ax + b = 32, x is a constant. If a = 3 when b = 2, what is a when b = 12?
10
13
7
2
3
2
The answer is 2.
First solve for the constant x:
3x + 2 = 32
x = 10
Now plug in x = 10 and b = 12:
a(10) + 12 = 32
a = 2
Example Question #4 : How To Evaluate Algebraic Expressions
A specialty socket wrench, typically priced at $29.99, is on sale for 30% off. An additional 45% is discounted at the register. What is the final sale price of the wrench?
$7.50
$22.49
$4.05
$11.55
$4.95
$11.55
The answer is $11.55
The original cost is $29.99 but we are going to discount 30%, meaning we will only pay 70%. The new prices is 29.99 x 0.70 = $20.99.
The new price is then dicounted an additional 45%, meaning we will only pay 55% of the new price. The final price is 20.99 x 0.55 = $11.55.
Example Question #8 : Evaluating Expressions
Quantitative Comparison
x is an integer.
Quantity A: (x + 1)2
Quantity B: (x – 1)2
Quantity B is greater.
The relationship cannot be determined from the information given.
Quantity A is greater.
The two quantities are equal.
The relationship cannot be determined from the information given.
When picking numbers, we should always try to plug in the numbers 0, 1, and –1 first.
First try 0:
(0 + 1)2 = 1
(0 – 1)2 = 1
Here the two quantities are equal.
Now try 1:
(1 + 1)2 = 4
(1 – 1)2 = 0.
Here Quantity A is greater.
Therefore the relationship cannot be determined.
Example Question #323 : Gre Quantitative Reasoning
Barry's workout today consists of 10 squats every minute on the minute and 6 situps every other minute for 1 hour. How many squats and situps does Barry do in total?
960
780
1000
1200
800
780
squats: 10 squats * 60 minutes = 600 squats
situps: 6 situps * 30 minutes = 180 situps
total = 600 + 180 = 780
Example Question #9 : Evaluating Expressions
Let and be integers such that and .
Quantity A Quantity B
0
The relationship cannot be determined from the information given
Quantity A and Quantity B are equal
Quantity A is greater
Quantity B is greater
The relationship cannot be determined from the information given
The quantity produces a minimum of and a maximum of 4, which are less than and greater than 0, respectively. Therefore, the answer cannot be determined from the information given.