GWD-TN 24 （ 15套） 30

ksm

?30. GWD21-Q30:
?In the past, most children who went sledding in the winter snow in Verland used wooden sleds with runners and steering bars.  Ten years ago, smooth plastic sleds became popular; they go faster than wooden sleds but are harder to steer and slow.  The concern that plastic sleds are more dangerous is clearly borne out by the fact that the number of children injured while sledding was much higher last winter than it was ten years ago.
?
?Which of the following, if true in Verland, most seriously undermines the force of the evidence cited?


?
A.A. A few children still use traditional wooden sleds.
B.B.Very few children wear any kind of protective gear, such as helmets, while sledding.
C.C.Plastic sleds can be used in a much wider variety of snow conditions than wooden sleds can.
D.D.Most sledding injuries occur when a sled collides with a tree, a rock, or, another sled.
E.E. Because the traditional wooden sled can carry more than one rider, an accident involving a wooden sled can result in several children being injured.

答案是C。 怎么想都觉得是D。求助，谢谢！

sdcar2010

Percentage vs. number.

Even though the number of accidents are up, it does not necessarily mean that the percentage of accidents goes up if the TOTAL number of such uses are way up. C) points out this possibility.

ksm

"use in much wider variety of snow conditions"  doesn't necessarily mean that the total injuries would increase. For instance, in the condition that no injuries would occur.

My question is: if the plastic sleds are harder to steer and slow, is it sufficient to imply that collisions with a tree, a rock, or, another sled would increase?

If yes, the C is the best answer.

sdcar2010

"use in much wider variety of snow conditions"  doesn't necessarily mean that the total injuries would increase. For instance, in the condition that no injuries would occur.

My question is: if the plastic sleds are harder to steer and slow, is it sufficient to imply that collisions with a tree, a rock, or, another sled would increase?

If yes, the C is the best answer.

-- by 会员 ksm (2011/7/23 12:40:10)

if the plastic sleds are harder to steer and slow, is it sufficient to imply that collisions with a tree, a rock, or, another sled would increase?

NO.

If the total number of using plastic sled is increasing (let's say increased 100%) and the number of injuries is increasing (but at a lower rate of 50%), then the plastic sled is not more dangerous (injury rate is decreasing by 33%).

ksm

"""If the total number of using plastic sled is increasing (let's say increased 100%) and the number of injuries is increasing (but at a lower rate of 50%), then the plastic sled is not more dangerous (injury rate is decreasing by 33%). """

Thus, C is not weakening the argument.

sdcar2010

"""If the total number of using plastic sled is increasing (let's say increased 100%) and the number of injuries is increasing (but at a lower rate of 50%), then the plastic sled is not more dangerous (injury rate is decreasing by 33%). """

Thus, C is not weakening the argument.

-- by 会员 ksm (2011/7/25 10:02:05)

Boy, you need to read the argument carefully. The main conclusion is:
The concern that plastic sleds are more dangerous ! ! !

sdcar2010

"""If the total number of using plastic sled is increasing (let's say increased 100%) and the number of injuries is increasing (but at a lower rate of 50%), then the plastic sled is not more dangerous (injury rate is decreasing by 33%). """

Thus, C is not weakening the argument.

-- by 会员 ksm (2011/7/25 10:02:05)

Boy, you need to read the argument carefully. The main conclusion is:
The plastic sleds are more dangerous ! ! !

ksm

Going back to your first reply, I think I get it.

However, in D,

"a sled collides with a tree, a rock, or, another sled" gives another explaination of increasing the injury---not because the plastic sleds are harder to control/stop (more dangerous), but because of these alternative reasons---- a typical way in GMAT to undermine the argument.

sdcar2010

Going back to your first reply, I think I get it.

However, in D,

"a sled collides with a tree, a rock, or, another sled" gives another explaination of increasing the injury---not because the plastic sleds are harder to control/stop (more dangerous), but because of these alternative reasons---- a typical way in GMAT to undermine the argument.

-- by 会员 ksm (2011/7/25 17:29:25)

No. You still did not get it.

"a sled collides with a tree, a rock, or, another sled" is NOT an alternative reason. It can happen to the old, wooden sleds, too.

ksm

honey, u r living on the internet la..
Yes, it can happen to the woden sleds which are not in our discussion.