CR- Parallel reasoning

Instructors! Can you please help in thsi CR question

vishalwin wrote:If the law punishes littering, then the city has an
obligation to provide trash cans. But the law does
not punish littering, so the city has no such
obligation.

Which one of the following exhibits a flawed pattern
of reasoning most similar to that in the argument
above?

(A) If today is a holiday, then the bakery will not be
open. The bakery is not open for business.
Thus today is a holiday.

(B) Jenny will have lots of balloons at her birthday
party. There are no balloons around yet, so
today is not her birthday.

(C) The new regulations will be successful only if
most of the students adhere to them. Since
most of the students will adhere to those
regulations, the new regulations will be
successful.

(D) In the event that my flight had been late, I
would have missed the committee meeting.
Fortunately, my flight is on time. Therefore, I
will make it to the meeting.

(E) When the law is enforced, some people are
jailed. But no one is in jail. So clearly the law
is not enforced.




Tough one!

Source: powerscore

Do I need to these kind of questions for GMAT. Also, I think the difficulty level is high.

Hmmm. This certainly feels like an LSAT question. I'll bite, but it's probably not worth your time to use LSAT resources for GMAT CR, as there are certain q-types that are common on the former and that you don't typically see on the latter.

The initial argument is: If the law punishes littering, then the city has an
obligation to provide trash cans. But the law does not punish littering, so the city has no such obligation.

In the abstract, the initial argument is x----> y
The faulty logic concludes that the Inverse is also true: Not x-----> Not y

(And you can see that this reasoning is not valid with simple examples. If I study for 20 hours for this test, I will pass, does not mean that if I DON'T study for 20 hours, I WON'T pass. It's possible I could study for 15 hours and pass. We don't know.)

The answer choice that has the same faulty reasoning is D

late flight---> missed meeting
x ----> y

Not x = flight is on time.
Not y = don't miss meeting

flight on time ----> don't miss meeting
Not x ------> Not y

Clearly this isn't valid. Even if the flight is on time, one could get stuck in traffic or get lost on the way to the meeting, etc.