The following GMAT data sufficiency question tests your understanding of average (arithmetic mean) in the context of being able to manipulate algebraic expressions and observe patterns.

Question 5:

What is the average (arithmetic mean) of $x$, $y$, and $z$ ?

1. (1) The average of $2x-5$, $2y-5$, $2z-5$ is $25$.
2. (2) The average of $2x-y$, $4y+3z$, and $x+9$ is $48$.

1. Statement (1) ALONE is sufficient, but statement (2) alone is not sufficient.
2. Statement (2) ALONE is sufficient, but statement (1) alone is not sufficient.
3. BOTH statements TOGETHER are sufficient, but NEITHER statement ALONE is sufficient.
4. EACH statement ALONE is sufficient.
5. Statements (1) and (2) TOGETHER are NOT sufficient.

 
The following GMAT Problem Solving question tests your understanding of how to simplify arithmetic expressions that use factorials.

Question 4:

$$\dfrac{(48!)(22!)(10!)(8!)}{(50!)(20!)(12!)(6!)}=$$

1. $\quad \dfrac{2}{25}$
2. $\quad \dfrac{3}{20}$
3. $\quad \dfrac{5}{18}$
4. $\quad \dfrac{6}{17}$
5. $\quad \dfrac{7}{15}$

 
The following GMAT Problem Solving question tests your understanding of how to deal with distance/rate/time questions.

Question 3:

Train $A$ and $B$, $455$ miles apart, are traveling towards each other on parallel tracks at constant rates and in the same time zone. If train $A$ left at $4$ pm traveling at a speed of $60$ miles per hour, and train $B$ left at $5:45$ pm traveling at $45$ miles per hour, then at what time would they pass each other?

1. $\quad 7:20 \; \textrm{pm}$
2. $\quad 8:55 \; \textrm{pm}$
3. $\quad 9:05 \; \textrm{pm}$
4. $\quad 9:20 \; \textrm{pm}$
5. $\quad 9:25 \; \textrm{pm}$

 
The following GMAT Problem Solving question tests your understanding of identifying identities and then applying them to simplify the computational effort.

Question 2:

$\dfrac{0.1001}{(-1.002)^2 – 1}=$

1. $\quad 0.025$
2. $\quad 0.25$
3. $\quad 2.5$
4. $\quad 25$
5. $\quad 250$