请教数学问题（一）--二战GMAT

ruoancheng

Q8:

The number of defects in the first five cars to come through a new production line are 9, 7, 10, 4, and 6, respectively.  If the sixth car through the production line has either 3, 7, or 12 defects, for which of theses values does the mean number of defects per car for the first six cars equal the median?





I. 3

II. 7

III. 12





A.I only

B.II only

C.III only

D.I and III only

E.I, II, and III

(D)

Q14:

The charge for a single room at Hotel P is 25 percent less than the charge for a single room at Hotel R and 10 percent less than the charge for a single room at Hotel G.  The charge for a single room at Hotel R is what percent greater than the charge for a single room at Hotel G ?



A.  15%

B.  20%

C.  40%

D.  50%

E. 150%

Answer: (B)

我的算出来是A，为什么是B呢？

Q20:

Of the 60 animals on a certain farm, are either pigs or cows.  How many of the animals are cows?

(1)  The farm has more than twice as many cows as it has pigs.

(2)  The farm has more than 12 pigs.



A. Statement (1) ALONE is sufficient, but statement (2) alone is not sufficient.

B. Statement (2) ALONE is sufficient, but statement (1) alone is not sufficient.

C. BOTH statements TOGETHER are sufficient, but NEITHER statement ALONE is sufficient.

D. EACH statement ALONE is sufficient.

E. Statements (1) and (2) TOGETHER are NOT sufficient.

Answer:(C)

我选择A， B为什么也对呢？

Q23:

On a certain transatlantic crossing, 20 percent of a ship’s passengers held round-trip tickets and also took their cars abroad the ship.  If 60 percent of the passengers with round-trip tickets did not take their cars abroad the ship, what percent of the ship’s passengers held round-trip tickets?



A. 33%

B. 40%

C. 50%

D. 60%

E. 66%

Answer: (C)

QX:  

On a certain transatlantic crossing, 20 percent of a ship’s passengers held round-trip tickets and also took their cars abroad the ship.  If 60 percent of the passengers with round-trip tickets did not take their cars abroad the ship, what percent of the ship’s passengers held round-trip tickets?



A. 20

B. 30
C. 50

D. 65

E. 70

Answer: (C)

Q25:

If M is the least common multiple of 90, 196, and 300, which of the following is NOT a factor of M ?



A.   600

B.   700

C.   900

D. 2,100

E. 4,900

Answer: （A）

Q26:

For each positive integer n, the integer n* is defined by n* = n2 + 1.  What is the value of the positive integer k ?

(1)  When k is divided by 4, the remainder is 1.

(2)  18 ≤ k* ≤ 36



A. Statement (1) ALONE is sufficient, but statement (2) alone is not sufficient.

B. Statement (2) ALONE is sufficient, but statement (1) alone is not sufficient.

C. BOTH statements TOGETHER are sufficient, but NEITHER statement ALONE is sufficient.

D. EACH statement ALONE is sufficient.

E. Statements (1) and (2) TOGETHER are NOT sufficient.

Answer: （B）