LSAT Forum
3 postsPage 1 of 1
-
- clairenlee
-
Thanks Received: 0
-
Vinny Gambini
- Posts: 11
- Joined: October 25th, 2010
PT17, S2, Q21; Nuclear reactors are sometimes built...
I just don't see the gap in this argument--probably why I also don't understand why C would be have to be assumed to make the argument valid. Could you help?
-
- bbirdwell
-
Thanks Received: 864
-
Atticus Finch
- Posts: 803
- Joined: April 16th, 2009
Re: PT17, S2, Q21; Nuclear reactors are sometimes built...
Interesting problem, no?
The gap is very small. For that reason, it's a great problem for practicing process of elimination. Even without spotting the specific gap beforehand, we ought to be able to eliminate several choices by simply identifying the conclusion.
Here's the argument:
1. quiet zones have only minor faults
2. minor faults don't make earthquakes more than once every 100,000 years.
Therefore, the nuclear reactor sites least likely to be struck by an earthquake are the ones near a fault that has recently had an earthquake.
It sounds pretty good at first glance, but "extreme" phrases like "least likely" should throw up red flags.
What if I said this:
No county in kansas has more than one tornado per year. Therefore, you are least likely to be caught in a tornado if you go to a county in kansas that has just had one.
Is that true? What if there's a county in Oregon that has NEVER had a tornado? Who said you HAD to be in Kansas?
What I'm getting at in the original argument is this:
If we can build a reactor that's not near ANY faults at all, there it would be even less likely to produce an earthquake. In other words, the conclusion assumes that we have to put it near a fault.
If we HAVE to put it near a fault, then yeah -- the best place is by a fault that's had an earthquake in recent memory. If we don't have to put it near a fault, there might be even better places.
Hopefully that explains the argument. Let's look at the choices and see how we might have arrived at the correct answer simply by focussing on the conclusion, as stated above.
(A) We don't need to compare quiet regions to other regions. The whole argument is about quiet regions, so this answer is out of scope.
(B) "Safety" has nothing to do with the argument -- the conclusion is limited to likelihood of earthquake. This answer is also out of scope.
(C) (pretend we don't know this is the answer, nor do we know the gap) It's got nuclear reactor, quiet zone, minor fault, and the conservative phrase "at least one." Let's keep it.
(D) "More than one?" "Of moderate force?" This is out of scope -- the conclusion makes no mention of force, and the author certainly does not assume that reactors can withstand one earthquake; the whole point seems to be to avoid earthquakes altogether.
(E) This is not necessary for the argument, either. What if some minor faults produce an earthquake once every million years? Wouldn't hurt our argument. The conclusion doesn't need earthquakes to happen once every 100,000 years -- the conclusion is simply based on evidence that says earthquakes never happen MORE than once every 100,000 years. If they happen less frequently, awesome, even better.
So right there, four choices are nowhere close, and one has some key components that stick out. If we have to guess, we'll guess (C).
Does that help?
The gap is very small. For that reason, it's a great problem for practicing process of elimination. Even without spotting the specific gap beforehand, we ought to be able to eliminate several choices by simply identifying the conclusion.
Here's the argument:
1. quiet zones have only minor faults
2. minor faults don't make earthquakes more than once every 100,000 years.
Therefore, the nuclear reactor sites least likely to be struck by an earthquake are the ones near a fault that has recently had an earthquake.
It sounds pretty good at first glance, but "extreme" phrases like "least likely" should throw up red flags.
What if I said this:
No county in kansas has more than one tornado per year. Therefore, you are least likely to be caught in a tornado if you go to a county in kansas that has just had one.
Is that true? What if there's a county in Oregon that has NEVER had a tornado? Who said you HAD to be in Kansas?
What I'm getting at in the original argument is this:
If we can build a reactor that's not near ANY faults at all, there it would be even less likely to produce an earthquake. In other words, the conclusion assumes that we have to put it near a fault.
If we HAVE to put it near a fault, then yeah -- the best place is by a fault that's had an earthquake in recent memory. If we don't have to put it near a fault, there might be even better places.
Hopefully that explains the argument. Let's look at the choices and see how we might have arrived at the correct answer simply by focussing on the conclusion, as stated above.
(A) We don't need to compare quiet regions to other regions. The whole argument is about quiet regions, so this answer is out of scope.
(B) "Safety" has nothing to do with the argument -- the conclusion is limited to likelihood of earthquake. This answer is also out of scope.
(C) (pretend we don't know this is the answer, nor do we know the gap) It's got nuclear reactor, quiet zone, minor fault, and the conservative phrase "at least one." Let's keep it.
(D) "More than one?" "Of moderate force?" This is out of scope -- the conclusion makes no mention of force, and the author certainly does not assume that reactors can withstand one earthquake; the whole point seems to be to avoid earthquakes altogether.
(E) This is not necessary for the argument, either. What if some minor faults produce an earthquake once every million years? Wouldn't hurt our argument. The conclusion doesn't need earthquakes to happen once every 100,000 years -- the conclusion is simply based on evidence that says earthquakes never happen MORE than once every 100,000 years. If they happen less frequently, awesome, even better.
So right there, four choices are nowhere close, and one has some key components that stick out. If we have to guess, we'll guess (C).
Does that help?
I host free online workshop/Q&A sessions called Zen and the Art of LSAT. You can find upcoming dates here: http://www.manhattanlsat.com/zen-and-the-art.cfm
-
- theanswer21324
-
Thanks Received: 0
- Forum Guests
- Posts: 27
- Joined: August 09th, 2013
Re: PT17, S2, Q21; Nuclear reactors are sometimes built...
This is a really frustrating problem since it stretches the bounds for what constitutes "common sense" within the realm of LSAT logic. 
The conclusion says that these reactors are the safest since they've already had an earthquake within living memory, and since we know that earthquakes happen no more than once in a 100,000 year period, we can conclude that an earthquake will not happen for another 100,000 years in this area.
If the earthquake doesn't happen for another 100,000 years, is it really acceptable to say that it is safer to have a reactor in a place where there is never going to be an earthquake over a reactor where there will not be another earthquake for ANOTHER 100,000 years?? 100,000 years is a REALLY long time - I suppose it will be bad for whoever is living then in the distant future, but still have no idea how you can compare these two things - they seem about the same if you use common sense. Who knows if we will even still be using nuclear power by then and not living on the moon?
This makes it hard for me to know whether the negation of the answer choice actually destroys the argument.
How far are we supposed to stretch our common sense for these types of problems?
The conclusion says that these reactors are the safest since they've already had an earthquake within living memory, and since we know that earthquakes happen no more than once in a 100,000 year period, we can conclude that an earthquake will not happen for another 100,000 years in this area.
If the earthquake doesn't happen for another 100,000 years, is it really acceptable to say that it is safer to have a reactor in a place where there is never going to be an earthquake over a reactor where there will not be another earthquake for ANOTHER 100,000 years?? 100,000 years is a REALLY long time - I suppose it will be bad for whoever is living then in the distant future, but still have no idea how you can compare these two things - they seem about the same if you use common sense. Who knows if we will even still be using nuclear power by then and not living on the moon?
This makes it hard for me to know whether the negation of the answer choice actually destroys the argument.
How far are we supposed to stretch our common sense for these types of problems?
3 posts Page 1 of 1