All GMAT Math Resources
Example Questions
Example Question #1 : Dsq: Understanding Rays
, , and are distinct points.
True or false: and are the same ray.
Statement 1: .
Statement 2: is the midpoint of .
Statement 2 ALONE is sufficient to answer the question, but Statement 1 ALONE is NOT sufficient to answer the question.
Statement 1 ALONE is sufficient to answer the question, but Statement 2 ALONE is NOT sufficient to answer the question.
BOTH statements TOGETHER are sufficient to answer the question, but NEITHER statement ALONE is sufficient to answer the question.
EITHER statement ALONE is sufficient to answer the question.
BOTH statements TOGETHER are insufficient to answer the question.
Statement 2 ALONE is sufficient to answer the question, but Statement 1 ALONE is NOT sufficient to answer the question.
We show Statement 1 alone is insufficient to determine whether the two rays are the same by looking at the figures below:
In both figures, , but only in the first figure, and are the same ray.
Assume Statement 2 alone. If is the midpoint of , must be on , as in the top figure, so and are one and the same.
Example Question #2 : Dsq: Understanding Rays
, , and are distinct points.
True or false: and are the same ray.
Statement 1:
Statement 2: .
BOTH statements TOGETHER are sufficient to answer the question, but NEITHER statement ALONE is sufficient to answer the question.
BOTH statements TOGETHER are insufficient to answer the question.
EITHER statement ALONE is sufficient to answer the question.
Statement 1 ALONE is sufficient to answer the question, but Statement 2 ALONE is NOT sufficient to answer the question.
Statement 2 ALONE is sufficient to answer the question, but Statement 1 ALONE is NOT sufficient to answer the question.
BOTH statements TOGETHER are insufficient to answer the question.
We show that both statements together provide insufficient information by giving two scenarios in which both statements are true.
Case 1: , , and are noncollinear. The three points are vertices of a triangle, and by the Triangle Inequality Theorem,
and
.
Also, since the three points are not on a single line, and are parts of different lines and cannot be the same ray.
Case 2: with length 2 and midpoint .
and , so ; similarly, . Also, and are the same ray, since they have the same endpoint and is on .
Example Question #3 : Dsq: Understanding Rays
, , and are distinct points.
True or false: and are the same ray.
Statement 1: , , and are collinear.
Statement 2: .
Statement 1 ALONE is sufficient to answer the question, but Statement 2 ALONE is NOT sufficient to answer the question.
BOTH statements TOGETHER are insufficient to answer the question.
Statement 2 ALONE is sufficient to answer the question, but Statement 1 ALONE is NOT sufficient to answer the question.
EITHER statement ALONE is sufficient to answer the question.
BOTH statements TOGETHER are sufficient to answer the question, but NEITHER statement ALONE is sufficient to answer the question.
Statement 2 ALONE is sufficient to answer the question, but Statement 1 ALONE is NOT sufficient to answer the question.
Statement 1 alone does not prove the rays to be the same or different, as seen in these diagrams:
In both figures, , , and are collinear, satisfying the condition of Statement 1. But In the top figure, and are the same ray, since is on ; in the bottom figure, since is not on , and are distinct rays.
Assume Statement 2 alone. Suppose and are not the same ray. Then one of two things happens:
Case 1: , , and are noncollinear. The three points are vertices of a triangle, and by the triangle inequality,
,
contradicting Statement 2.
Case 2: , , and are collinear. must be between and , as in the bottom figure, since if it were not, and would be the same ray. By segment addition,
,
contradicting Statement 2.
By contradiction, and are the same ray.
Example Question #11 : Geometry
What is the measure of ?
Statement 1: is complementary to an angle that measures .
Statement 2: is adjacent to an angle that measures .
EITHER statement ALONE is sufficient to answer the question.
Statement 1 ALONE is sufficient to answer the question, but Statement 2 ALONE is NOT sufficient to answer the question.
BOTH statements TOGETHER are insufficient to answer the question.
BOTH statements TOGETHER are sufficient to answer the question, but NEITHER statement ALONE is sufficient to answer the question.
Statement 2 ALONE is sufficient to answer the question, but Statement 1 ALONE is NOT sufficient to answer the question.
Statement 1 ALONE is sufficient to answer the question, but Statement 2 ALONE is NOT sufficient to answer the question.
Complementary angles have degree measures that total , so the measure of an angle complementary to a angle would have measure . If Statement 1 is assumed, then .
Statement 2 gives no useful information. Adjacent angles do not have any numerical relationship; they simply share a ray and a vertex.
Example Question #2241 : Gmat Quantitative Reasoning
Note: Figure NOT drawn to scale.
Refer to the above diagram.
What is the measure of ?
Statement 1:
Statement 2:
EITHER statement ALONE is sufficient to answer the question.
Statement 2 ALONE is sufficient to answer the question, but Statement 1 ALONE is NOT sufficient to answer the question.
BOTH statements TOGETHER are sufficient to answer the question, but NEITHER statement ALONE is sufficient to answer the question.
Statement 1 ALONE is sufficient to answer the question, but Statement 2 ALONE is NOT sufficient to answer the question.
BOTH statements TOGETHER are insufficient to answer the question.
Statement 2 ALONE is sufficient to answer the question, but Statement 1 ALONE is NOT sufficient to answer the question.
If we only know that , then we cannot surmise anything from the diagram about the measure of . But and are vertical angles, which must be congruent, so if we know , then also.
Example Question #13 : Geometry
and are supplementary angles. Which one has the greater measure?
Statement 1:
Statement 2: is an obtuse angle.
Statement 1 ALONE is sufficient to answer the question, but Statement 2 ALONE is NOT sufficient to answer the question.
BOTH statements TOGETHER are sufficient to answer the question, but NEITHER statement ALONE is sufficient to answer the question.
EITHER statement ALONE is sufficient to answer the question.
Statement 2 ALONE is sufficient to answer the question, but Statement 1 ALONE is NOT sufficient to answer the question.
BOTH statements TOGETHER are insufficient to answer the question.
Statement 2 ALONE is sufficient to answer the question, but Statement 1 ALONE is NOT sufficient to answer the question.
By definition, if and are supplementary angles, then .
If Statement 1 is assumed and , then . This does not answer our question, since, for example, it is possible that and , or vice versa.
If Statement 2 is assumed, then , and subsequently, ; by transitivity, .
Example Question #2242 : Gmat Quantitative Reasoning
Note: Figure NOT drawn to scale.
Refer to the above diagram. What is the measure of ?
Statement 1:
Statement 2: is a angle.
Statement 2 ALONE is sufficient to answer the question, but Statement 1 ALONE is NOT sufficient to answer the question.
BOTH statements TOGETHER are insufficient to answer the question.
BOTH statements TOGETHER are sufficient to answer the question, but NEITHER statement ALONE is sufficient to answer the question.
EITHER statement ALONE is sufficient to answer the question.
Statement 1 ALONE is sufficient to answer the question, but Statement 2 ALONE is NOT sufficient to answer the question.
EITHER statement ALONE is sufficient to answer the question.
Assume Statement 1 alone. Since and form a linear pair, their measures total . Therefore, this fact, along with Statement 1, form a system of linear equations, which can be solved as follows:
The second equation can be rewritten as
and a substitution can be made:
Assume Statement 2 alone. and are a pair of vertical angles, which have the same measure, so .
Example Question #3 : Dsq: Calculating An Angle Of A Line
Note: You may assume that and are not parallel lines, but you may not assume that and are parallel lines unless it is specifically stated.
Refer to the above diagram. Is the sum of the measures of and less than, equal to, or greater than ?
Statement 1:
Statement 2:
Statement 1 ALONE is sufficient to answer the question, but Statement 2 ALONE is NOT sufficient to answer the question.
Statement 2 ALONE is sufficient to answer the question, but Statement 1 ALONE is NOT sufficient to answer the question.
BOTH statements TOGETHER are sufficient to answer the question, but NEITHER statement ALONE is sufficient to answer the question.
BOTH statements TOGETHER are insufficient to answer the question.
EITHER statement ALONE is sufficient to answer the question.
EITHER statement ALONE is sufficient to answer the question.
Assume Statement 1 alone. and form a linear pair of angles, so their measures total ; the same holds for and . Therefore,
Assume Statement 2 alone. and form a linear pair of angles, so their measures total ; the same holds for and . Therefore,
, , , and are the four angles of Quadrilateral , so their degree measures total 360. Therefore,
Example Question #6 : Dsq: Calculating An Angle Of A Line
Find the angle made by and the -axis.
I) goes through the origin and the point .
II) makes a degree angle between itself and the -axis.
Both statements are needed to answer the question.
Statement II is sufficient to answer the question, but statement I is not sufficient to answer the question.
Either statement is sufficient to answer the question.
Neither statement is sufficient to answer the question. More information is needed.
Statement I is sufficient to answer the question, but statement II is not sufficient to answer the question.
Either statement is sufficient to answer the question.
To find the angle of the line, recall that each quadrant has 90 degrees
I) Tells us that the line has a slope of one. This means that if we make a triangle using our line, the x-axis and a line coming up from the x-axis at 90 degrees we will have a 45/45/90 triangle. Therefore, I) tells us that our angle is 45 degrees.
II) Tells us that the line makes a 45 degree angle between itself and the y-axis. Therefore:
Therfore, we could use either statement.
Example Question #3 : Dsq: Calculating An Angle Of A Line
Note: Figure NOT drawn to scale.
Refer to the above diagram. What is the measure of ?
Statement 1:
Statement 2:
EITHER statement ALONE is sufficient to answer the question.
BOTH statements TOGETHER are insufficient to answer the question.
BOTH statements TOGETHER are sufficient to answer the question, but NEITHER statement ALONE is sufficient to answer the question.
Statement 2 ALONE is sufficient to answer the question, but Statement 1 ALONE is NOT sufficient to answer the question.
Statement 1 ALONE is sufficient to answer the question, but Statement 2 ALONE is NOT sufficient to answer the question.
Statement 2 ALONE is sufficient to answer the question, but Statement 1 ALONE is NOT sufficient to answer the question.
Assume Statement 1 alone. and are a pair of vertical angles and are therefore congruent, so the statement
can be rewritten as
, , and together form a straight angle, so their measures total ; therefore,
But without further information, the measure of cannot be calculated.
Assume Statement 2 alone. and are a pair of vertical angles and are therefore congruent, so the statement
can be rewritten as