A set of 10 practice questions similar to those found on the GRE Quantitative Reasoning section is presented below. Each question includes options and a step-by-step solution provided below.
A car covered 130 miles using 4 gallons of diesel fuel. What distance would the same car cover, under similar conditions, using 6.7 gallons?
A) 77
B) 260.25
C) 520
D) 217.75
E) 871
Set up a direct proportion based on fuel consumption:
\[ \dfrac{130 \text{ miles}}{4 \text{ gallons}} = \dfrac{x \text{ miles}}{6.7 \text{ gallons}} \]Solve for \(x\):
\[ x = \dfrac{130 \times 6.7}{4} = \dfrac{871}{4} = 217.75 \]Answer: D) 217.75
If plotted on the same rectangular coordinate system, the graphs of
\[ f(x) = \left||x| - 4\right| \quad \text{and} \quad g(x) = 2 \]will have how many points of intersection?
A) No points of intersection
B) 1 point of intersection
C) 2 points of intersection
D) 3 points of intersection
E) 4 points of intersection
Set the two equations equal to each other to find points of intersection:
\[ \left||x| - 4\right| = 2 \]This gives two possibilities for the inner absolute value:
\[ |x| - 4 = 2 \quad \text{or} \quad |x| - 4 = -2 \]In total, there are 4 distinct points of intersection.
Answer: E) 4 points of intersection
Which of the following numbers is the largest?
A) \(125\%\)
B) \(1.25\)
C) \(1 + \dfrac{1}{3}\)
D) \( \dfrac{4}{3}\)
E) \( \dfrac{0.0015}{0.001}\)
Convert each option into decimal format for comparison:
Comparing the values, \(1.5\) (Option E) is the largest.
Answer: E) \( \dfrac{0.0015}{0.001}\)
Evaluate the expression:
\[ \left|\left|-10 - 19\right| - 20\right| \]A) 9
B) 49
C) \(-49\)
D) 19
E) 11
Evaluate step-by-step from the innermost absolute value outward:
Answer: A) 9
The algebraic expression
\[ \dfrac{x}{x + 2} \]is undefined for which value of \(x\)?
A) 0
B) 1
C) 2
D) \(-2\)
E) \(-1\)
A rational expression is undefined where its denominator equals zero:
\[ x + 2 = 0 \implies x = -2 \]Answer: D) \(-2\)
Evaluate:
\[ (\sqrt{5} - \sqrt{7})(\sqrt{5} + \sqrt{7}) \]A) 12
B) 2
C) 24
D) \(-24\)
E) \(-2\)
Use the difference of squares identity \((a - b)(a + b) = a^2 - b^2\):
\[ (\sqrt{5})^2 - (\sqrt{7})^2 = 5 - 7 = -2 \]Answer: E) \(-2\)
In the figure below, the sides \(AB\) and \(AC\) of triangle \(ABC\) have equal lengths. Find the measure of angle \(\angle ABC\).
A) \(46^\circ\)
B) \(67^\circ\)
C) \(134^\circ\)
D) \(136^\circ\)
E) Cannot be calculated using the given information
Since \(AB = AC\), triangle ABC is isosceles. The angles opposite to the equal sides are also equal. Using triangle angle sum properties with the given vertex angle yields \(67^\circ\).
Answer: B) \(67^\circ\)
If \(y = 10^\circ\) in the figure below, what is the value of \(x\)?
A) \(20^\circ\)
B) \(30^\circ\)
C) \(10^\circ\)
D) \(5^\circ\)
E) \(15^\circ\)
Using the property that the sum of all interior angles in a triangle is equal to \(180^\circ\), we sum the given angle expressions:
\[ (4x + 4y) + (x + 3y) + (x + 2y) = 180^\circ \]Combine like terms to simplify the equation:
\[ 6x + 9y = 180^\circ \]Substitute the known value \(y = 10^\circ\) into the equation:
\[ 6x + 9(10^\circ) = 180^\circ \] \[ 6x + 90^\circ = 180^\circ \] \[ 6x = 90^\circ \implies x = \dfrac{90^\circ}{6} = 15^\circ \]Answer: E) \(15^\circ\)
By what percent will the volume of a rectangular solid increase if its length, width, and height each increase by \(25\%\)?
A) 25%
B) 95%
C) 74%
D) 15.6%
E) 50%
Let original dimensions be \(L\), \(W\), and \(H\). Original Volume \(V_1 = LWH\).
Each dimension increases by \(25\%\), becoming \(1.25L\), \(1.25W\), and \(1.25H\).
New Volume \(V_2 = (1.25L)(1.25W)(1.25H) = (1.25)^3 LWH = 1.953125 \, LWH\).
Percentage increase = \((1.953125 - 1) \times 100\% = 95.3125\%\), which rounds to \(95\%\).
Answer: B) 95%
What is the average of all prime numbers between 20 and 40?
A) 20
B) 25
C) 30
D) 35
E) 40
Identify all prime numbers between 20 and 40:
\[ 23, \quad 29, \quad 31, \quad 37 \]Calculate their sum:
\[ 23 + 29 + 31 + 37 = 120 \]Calculate the average by dividing the sum by the count (4):
\[ \text{Average} = \dfrac{120}{4} = 30 \]Answer: C) 30