一道CR，想不通

Kilroy

Investigators that concluded that human failure was not repsonsible for the fatal air crash last Aug, and since that time new and more strigent rules for identifying and reporting mechanical problems hv been in effect. That accounts for the fact that reports of airplane mechanical problems hv increased in frenqucy by 50 percent since last Aug.
Which one of the following is the an assumption underlying the argument in the passage?
(A) Airplane is still relatively safe, despite the increase in reported mechanical problems
(B) mechanical problems in airplane hv increased in frenqucy dramatically since last Aug.
(C) mechanical problems in airplance hv not increased in frenqucy by 50 percent since last Aug.
(D) Airline are less reluctant to report mechanical problems than they previously were
(E) Mechanical problems in airplanes hv become easier to detect since last Aug.







answer: C
请问怎么解释

Kilroy

Thank c800 for ur explanation!
I think i am much more clear.

c800

Kilroy, Let me try again. Open for discussion. 1 怎么从The conclusion is ”human failure was not responsible for the fatal air crash”推出The line of reasoning implied “出事后，制订了严格的措施is the only factor” accounts for “事故报告率增高了50%”？ Please be advised that the conclusion is made from the line of reasoning. First, from the argument you find the line of reasoning in the argument is “出事后，制订了严格的措施” accounts for “事故报告率增高了50%” Then, it is concluded that ”human failure was not responsible for the fatal air crash” To reach the conclusion, it must assumed that “严格的措施"is the only factor accounts for “事故报告率增高了50%” But since there is no such assumption stated in the argument, you need (C) to sthrengthen the argument. 2 如果答案C改成 mechanical problems in airplance hv increased in frenqucy by 50 percent since last Aug.是否正确？ thx! As long as it <=50%, it is ok. My experience is that nothing is perfect in GMAT. You only need to pick up the best one. I believe the modification is ok since it is still the best.

Kilroy

thank everybody for being so helpful!
我还是想把这道题目彻底搞搞懂。
我现在主要有两个疑问：
1 怎么从The conclusion is ”human failure was not responsible for the fatal air crash”推出The line of reasoning implied “出事后，制订了严格的措施is the only factor” accounts for “事故报告率增高了50%”？
2 如果答案C改成 mechanical problems in airplance hv increased in frenqucy by 50 percent since last Aug.是否正确？
thx!

c800

Sorry, the above message should be addressed to Kilroy.

c800

qiufeng1990：
Let me have to try to explain it. Hope it helps.

The conclusion is ”human failure was not responsible for the fatal air crash”
The line of reasoning implied “出事后，制订了严格的措施is the only factor” accounts for “事故报告率增高了50%”
To make the reasoning valid, the argument at least have to make an assumption (C) 实际没有那末多.
Without (C), suppose实际mechanical problems > 50%, say 60%, then at least some other factors must account for the additional 10%. If so, the reasoning “措施is the only factor” accounts for “事故报告率增高” is flawed, thus the conclusion ”human failure was not responsible for the fatal air crash” is weakened .

tongxun

文中主要想说的是：出事后，制订了严格的措施，事故报告率增高了50%。后两句才是作者的主题。

Kilroy

还是不明白！
文中的arugment的主题如果是human failure was not repsonsible for the fatal air crash，答案C还是解释不通

Kilroy

还是不明白！
文中的arugment的主题如果是human failure was not repsonsible for the fatal air crash，答案C还是解释不通

tongxun

真的，你来后，帮了我的大忙！！！！