GWD 数学

cd1123

我做GWD数学的时候，发现很多和GWD的答案不一样，望高手指点
GWD2-Math

Q5:
The interior of a rectangular carton is designed by a certain manufacturer to have a volume of x cubic feet and a ratio of length to width to height of 3:2:2.  In terms of x, which of the following equals the height of the carton, in feet?

A.   3√x
B.    3√[(2x)/3]
C.   3√[(3x)/2]
D.   (2/3) 3√x
E.    (3/2) 3√x
my Key: B, GWD的答案是A

The figure shown represents a board with 4 rows of pegs, and at the bottom of the board are 4 cells numbered 1 to 4.  Whenever the ball shown passes through the opening between two adjacent pegs in the same row, it will hit the peg directly beneath the opening.  The ball then has the probability 1/2 of passing through the opening immediately to the left of that peg and probability 1/2 of passing through the opening immediately to the right.  What is the probability that when the ball passes through the first two pegs at the top it will end in Cell 2?

A.   1/16
B.    1/8
C.   1/4
D.   3/8
E.    1/2
my answer: D 3/8, GWD : E

Q17:
Meg and Bob are among the 5 participants in a cycling race.  If each participant finishes the race and no two participants finish at the same time, in how many different possible orders can the participants finish the race so that Meg finishes ahead of Bob?

A.     24
B.     30
C.     60
D.     90
E.      120
Key: C, GWD的答案是B
P(5,5) / 2 = 60, M在B前的次数和B在M前的相等，所以平分。


Q22:
If x is negative, is x  9
(2) x3 < -9
mt Key: A, GWD的答案是C

GWD2-GMAT

Q6: The figure above shows the dimensions of a semicircular cross section of a one-way tunnel.  The single traffic lane is 12 feet wide and is equidistant from the sides of the tunnel.  If vehicles must clear the top of the tunnel by at least &frac12; foot when they are inside the traffic lane, what should be the limit on the height of vehicles that are allowed to use the tunnel?

A.     5&frac12; ft
B.     7&frac12; ft
C.     8 &frac12; ft
D.     9&frac12; ft
E.      10 ft
my kEY: b   GWD的答案是E好象不对。


Q18:
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 1/3%
B.     40%
C.     50%
D.     60%
E.      66 2/3%

my answer:C, GWD的答案是D

sammen

Q5我作出来也是B；4题是不是有图的啊？Q17我和你是一样的。Q22问的是什么啊？X是9吗？Q18我也是C。很奇怪啊，我也高不明白了。

cd1123

Q22. If x is negative, is x < -3?

(1) x2 > 9

(2) x3 < -9

my Key: A, GWD的答案是C

第4题是有图的。但是考不上来。

Q6: The figure above shows the dimensions of a semicircular cross section of a one-way tunnel. The single traffic lane is 12 feet wide and is equidistant from the sides of the tunnel. If vehicles must clear the top of the tunnel by at least ½ foot when they are inside the traffic lane, what should be the limit on the height of vehicles that are allowed to use the tunnel? A. 5½ ft B. 7½ ft C. 8 ½ ft D. 9½ ft E. 10 ft my kEY: b GWD的答案是E好象不对。

robert

GWD上的很多答案都不对，所以最好做完后拿到这里讨论一下