GMAT 逻辑分析题 (8)

sdcar2010

If there is any fierce competition in the Asian Games in Guangzhou, the attending audience will be treated to a mesmerizing and memorable moment. But there will not be a mesmerizing and memorable moment unless there are diehard sports fans in the audience. To be a diehard sports fan, one must understand the spirit of sports.

If all the statements above are true, which one of the following statements must also be true?

A) If there are no diehard sports fans in the audience, then there will be no fierce competition in the Asian Games in Guangzhou.

B) No people who understand the spirit of sports will be in the audience if the audience will not be treated to a mesmerizing and memorable moment.

C) If there will be people in the audience who understand the spirit of sports, then at least one competition in the Asian Games in Guangzhou will be fierce.

D) The audience will be treated to a mesmerizing and memorable moment unless there are people in the audience who do not understand the spirit of sports.

E) If there are diehard sports fans in the audience, then there will be fierce competition in the Asian Games in Guangzhou.

sdcar2010

Yes, we got a winner!

sdcar2010

This is a formal logic problem. In formal logic, recognition of trigger is very important. Trigger is the sufficient condition in an If ..., then ... statement.

From the stimulus:
But there will not be a mesmerizing and memorable moment unless there are diehard sports fans in the audience.
Or in If/then form:
If there are NOT diehard sports fans in the audience, then there will not be a mesmerizing and memorable moment.

There is not statement in the stimulus with "diehard sports fans" as the trigger (sufficient condition). Therefore, E) is wrong.

sdcar2010

could anyone pls explain why C is not right?

-- by 会员 alex168 (2011/7/3 3:57:58)

The reason is the same: no trigger for C).

The last sentence in the stimulus:
To be a diehard sports fan, one must understand the spirit of sports.
Or: If one is a diehard sports fan, then one understands the spirit of sports.
Note: "one understands the spirit of sports" is not a sufficient condition (trigger).
C) If there will be people in the audience who understand the spirit of sports, then at least one competition in the Asian Games in Guangzhou will be fierce.

C) needs "one understands the spirit of sports" to be a trigger. However, no trigger can be found in the stimulus.

sdcar2010

If there is any fierce competition in the Asian Games in Guangzhou, the attending audience will be treated to a mesmerizing and memorable moment. But there will not be a mesmerizing and memorable moment unless there are diehard sports fans in the audience. To be a diehard sports fan, one must understand the spirit of sports.

Fierce competition --> m&m moment
m&m moment --> diehard fans
diehard fans --> understand the spirit of sports.

Inference:
1) Fierce competition --> diehard fans
2) Fierce competition --> understand spirit of sports
3) m&m moment --> understand the spirit of sports

sdcar2010

Fierce competition --> m&m moment
m&m moment --> diehard fans

If you acknowledge the above premises, then their contrapositives are correct:
No diehard fans --> No m&m moment
No m&m moment --> No fierce competition

Therefore, No diehard fans --> No fierce competition

For formal logic questions in CR, do not add your own objective/subjective opinions to the logic chains in the passage. Remember, we are analyzing the author's logic reasonings here, not yours. ONLY focus on the logic statements in the passage and go from there.

sdcar2010

Thks NN for the explanations.

My summary from this question:
1. A unless B: A ->B (after UNLESS is a necessary condition)
2. To / in order to represents the if-part in if-then statements.

-- by 会员 AlohaDJ (2011/8/10 1:37:05)

A unless B:   Not A --> B (You have to negate the claim in A to make it a sufficient condition).

Not A unless B: A --> B

sdcar2010

sdcar, I have a question about the trigger. Is it something that appears in the stimulus? I saw you say sufficient conditon, so I think the trigger must appear as it does in the stimulus, am I right?

-- by 会员 corrine90 (2011/8/20 9:52:35)

That's right. The trigger is the sufficient condition in a logic statement. Because without the trigger, you won't logically reach the necessary condition.