以下是GMAT考试的一些样例试题：

1. If x and y are both positive integers, which of the following could be the value of x - y?

(A) -5
(B) -1
(C) 0
(D) 1
(E) 5

2. If 3x - 2y = 10, what is the value of y in terms of x?

(A) y = 3x - 10
(B) y = (3/2)x - 5
(C) y = (3/2)x + 5
(D) y = (2/3)x - 5
(E) y = (2/3)x + 5

3. If x is an odd integer, which of the following must be an even integer?

(A) x + 1
(B) x - 1
(C) 2x
(D) 3x
(E) x/2

4. If 3x + 2y = 12 and 2x - 3y = 6, what is the value of x + y?

(A) 2
(B) 3
(C) 4
(D) 5
(E) 6

5. If a certain company has 500 employees, and 40% of them are women, how many of the employees are men?

(A) 100
(B) 200
(C) 250
(D) 300
(E) 400

6. If x and y are both positive integers, and x + y = 10, what is the maximum possible value of xy?

(A) 20
(B) 25
(C) 30
(D) 36
(E) 50

7. If a certain car travels 60 miles in 1 hour, how many miles will it travel in 3 hours?

(A) 120
(B) 150
(C) 180
(D) 200
(E) 220

8. If a certain investment increases by 25% in the first year, and then decreases by 20% in the second year, what is the net percentage change in the investment?

(A) 5%
(B) 10%
(C) 15%
(D) 20%
(E) 25%