LR Strategy Guide - Drill Questions

[LSAT-Chang]

Came across 2 drill questions in the LR Strategy guide which I didn't agree with the correct answer... anyone please help!

1. In page 99, Drill question #3, why wouldn't "Total costs for Chad's Burger Shack were not lower in July than they were in April" be a necessary assumption? The explanation just says: This is irrelevant. Costs have nothing to do with revenue. But doesn't cost mean spending? If so, then I would assume that if Chad's Burger Shack was spending less in July than they were in April, it would totally destroy the argument since then, it wouldn't necessarily be that they sold MORE burgers, but rather they had higher revenue because their expenditures decreased. Or does costs not equal spending? I might have misunderstood the term "cost" - I am not an economics major, have zero knowledge, but if this is something basic that I need to know, please help me understand the term!

2. In the same page 99, Drill question #5, why wouldn't "The bell never fails to ring when a customer enters the front door of the store" be necessary? The assumptions that I had after reading the argument was: well, we must assume that the bell isn't broken, and we also should assume that customers aren't walking in and out several times (for example, needing to pick up the phone outside and then re-entering = that wouldn't be an accurate determination of number of customers since you could possibly count 2 ring bells as 2 customers when it might have been just one). So from my first assumption, that we must assume that the bell isn't broken, I thought "oh yeah! we definitely need to assume that the bell never fails to ring when a customer enters the front door of the store" since if we negate it, we get "the bell sometimes fails to ring when a customer enters the front door of the store" which would definitely destroy the conclusion since again, that won't be an accurate determination of the number of customers! Right..? Or would it be necessary if it said "The bell SOMETIMES does not fail to ring when a customer enters the front door of the store"? Okay I think I'm stretching this out too much. I am so confused now.

[noah]

1. In page 99, Drill question #3, why wouldn't "Total costs for Chad's Burger Shack were not lower in July than they were in April" be a necessary assumption?

You'd be correct if the answer said "The sole reason for revenue increasing was not because costs were lower in July than in April." But - and now I'm talking about the negation of the original answer choice - even if lowered costs in July could increase revenue, it would have to completely account for the differential in revenue to destroy the argument.

Analogously, consider this argument: I'm healthier now than I was a year ago, thus I must have started eating better.

I bet you can think of debate points for that. For example, it could be that I'm living in a less polluted place and that's why I'm healthier. So, is "I'm not living in a less polluted place" a necessary assumption? No, I don't have to assume that. I could live in a less polluted place but the reason for my being healthier might still be that I'm eating better. Make sense?

BTW, revenue is different than profit. Revenue is just the money you take in. Subtract the costs and you get profit.

2. In the same page 99, Drill question #5, why wouldn't "The bell never fails to ring when a customer enters the front door of the store" be necessary? ....if we negate it, we get "the bell sometimes fails to ring when a customer enters the front door of the store" which would definitely destroy the conclusion since again, that won't be an accurate determination of the number of customers! Right..?

You're right - if you negate this answer choice, the argument doesn't make sense. But, that's because it's restating the premise ("...whenever a customer enters..."). We want an assumption that when you negate it, you can no longer draw the conclusion from the given premise. What we wanted to point out there is that an assumption is something that is unstated in the argument, so eliminate premise booster and conclusion repeaters. So, don't just use the negation test blindly.

In my opinion, and my colleagues might disagree here, the LSAT probably wouldn't serve up that answer choice, for the reason you brought up - good catch! - but I'm happy to have it there to keep folks eyes on the assumption prize.

[LSAT-Chang]

Analogously, consider this argument: I'm healthier now than I was a year ago, thus I must have started eating better.

I bet you can think of debate points for that. For example, it could be that I'm living in a less polluted place and that's why I'm healthier. So, is "I'm not living in a less polluted place" a necessary assumption? No, I don't have to assume that. I could live in a less polluted place but the reason for my being healthier might still be that I'm eating better. Make sense?

Not really.. when I first read your argument, this was my thought process:

1. Okay, the author's argument is that the only reason he is healthier now is because he started eating better.
2. Well, like you pointed out, there could be tons of other reasons why he is healthier and not necessarily that he started eating better. He could have exercised a lot more this year than in the previous year, he could have moved to a less polluted area a few months ago and his health improved, etc.
3. From what I recalled in our session 3 class last week, the TRAIN example came to my mind: the train departed on time therefore the train arrived on time. Well, there are ton of assumptions that the author is making: the train didn't crash, the train didn't get delayed on one of the stops, etc. And from what I recall, the point is to fill the gap partially so we would have to spot one of the assumptions such as "the train didn't crash". So a correct answer choice might be something like "the train didn't crash on its way to its destination" or something. We would HAVE to assume that since or else, the conclusion would not hold -- it could not have arrived on time.
4. The analogy that you provided sounds similar since it is saying that he MUST have started eating better, so wouldn't we have to eliminate other possibilities (not necessarily ALL since it is a necessary assumption question) such as "I'm not living in a less polluted place" for the argument to hold? Because if we didn't assume that, then there is room for us to think "well, you may have moved to a less polluted place that significantly improved your health -- so we don't know for sure that it MUST have been you eating better." Right??

[noah]

1. Okay, the author's argument is that the only reason he is healthier now is because he started eating better.

Agreed.

2. Well, like you pointed out, there could be tons of other reasons why he is healthier and not necessarily that he started eating better. He could have exercised a lot more this year than in the previous year, he could have moved to a less polluted area a few months ago and his health improved, etc.

Agreed.

3. From what I recalled in our session 3 class last week, the TRAIN example came to my mind: the train departed on time therefore the train arrived on time. Well, there are ton of assumptions that the author is making: the train didn't crash, the train didn't get delayed on one of the stops, etc. And from what I recall, the point is to fill the gap partially so we would have to spot one of the assumptions such as "the train didn't crash". So a correct answer choice might be something like "the train didn't crash on its way to its destination" or something. We would HAVE to assume that since or else, the conclusion would not hold -- it could not have arrived on time.

Each of those train assumptions would make the train arrive late (unless we're going to somehow argue that crashing doesn't make a train late!). Would living in a less-polluted place definitely mean that eating better is not the reason for the improved health? The diet still could be the reason and the move could be irrelevant.

4. The analogy that you provided sounds similar since it is saying that he MUST have started eating better, so wouldn't we have to eliminate other possibilities (not necessarily ALL since it is a necessary assumption question) such as "I'm not living in a less polluted place" for the argument to hold? Because if we didn't assume that, then there is room for us to think "well, you may have moved to a less polluted place that significantly improved your health -- so we don't know for sure that it MUST have been you eating better." Right??

Would we have to eliminate the possibility that I also started wearing red hats? It's pretty obvious that we wouldn't have to, since it's hard to imagine the hat color affecting my health. However, I do have to assume that "switching to wearing a red hat is not the reason I became more healthy." If it was the reason, I couldn't draw the conclusion about the diet.

For you to say that not moving to a less polluted place is a necessary assumption means that you are assuming that such a move definitely affects health. Perhaps it doesn't.

[LSAT-Chang]

1. Okay, the author's argument is that the only reason he is healthier now is because he started eating better.

Agreed.

2. Well, like you pointed out, there could be tons of other reasons why he is healthier and not necessarily that he started eating better. He could have exercised a lot more this year than in the previous year, he could have moved to a less polluted area a few months ago and his health improved, etc.

Agreed.

3. From what I recalled in our session 3 class last week, the TRAIN example came to my mind: the train departed on time therefore the train arrived on time. Well, there are ton of assumptions that the author is making: the train didn't crash, the train didn't get delayed on one of the stops, etc. And from what I recall, the point is to fill the gap partially so we would have to spot one of the assumptions such as "the train didn't crash". So a correct answer choice might be something like "the train didn't crash on its way to its destination" or something. We would HAVE to assume that since or else, the conclusion would not hold -- it could not have arrived on time.

Each of those train assumptions would make the train arrive late (unless we're going to somehow argue that crashing doesn't make a train late!). Would living in a less-polluted place definitely mean that eating better is not the reason for the improved health? The diet still could be the reason and the move could be irrelevant.

4. The analogy that you provided sounds similar since it is saying that he MUST have started eating better, so wouldn't we have to eliminate other possibilities (not necessarily ALL since it is a necessary assumption question) such as "I'm not living in a less polluted place" for the argument to hold? Because if we didn't assume that, then there is room for us to think "well, you may have moved to a less polluted place that significantly improved your health -- so we don't know for sure that it MUST have been you eating better." Right??

Would we have to eliminate the possibility that I also started wearing red hats? It's pretty obvious that we wouldn't have to, since it's hard to imagine the hat color affecting my health. However, I do have to assume that "switching to wearing a red hat is not the reason I became more healthy." If it was the reason, I couldn't draw the conclusion about the diet.

For you to say that not moving to a less polluted place is a necessary assumption means that you are assuming that such a move definitely affects health. Perhaps it doesn't.

Okay.. how about "switching to a less polluted area is not the reason I became more healthy"? Or are you saying we don't have to assume ANYTHING about polluted areas? I guess I'm not seeing the difference between:

"switching to wearing a red hat is not the reason I became more healthy" and "switching to a less polluted area is not the reason I became more healthy"

I clearly understand that he could have moved to a less polluted area but that his diet still was the only factor that resulted in him being healthy, but isn't that the same with red hats? He could have still wore red hats but the only factor was him eating better that resulted in him being healthier.

Or even better.. if you can, could you think of one necessary assumption that deals with pollution that we would have to assume?? Is it just because the train example and this example is just really different? so we would HAVE to assume something about the train not crashing since it wouldn't arrive on time whereas pollution and eating better can co-exist and we still could have the eating better as the only reason while living in a less polluted area?

[noah]

Right. The train example and this are different in that the "problems" in those assumptions would actually make the conclusion impossible.

As you say, if the assumption were "switching to a less polluted area is not the reason I became more healthy" - then it would be necessary. Negate it, and the argument falls apart.

Nice work.

[LSAT-Chang]

Right. The train example and this are different in that the "problems" in those assumptions would actually make the conclusion impossible.

As you say, if the assumption were "switching to a less polluted area is not the reason I became more healthy" - then it would be necessary. Negate it, and the argument falls apart.

Nice work.

Ha, I get it now!! "I'm not living in a less polluted place" is totally different from "Switching to a less polluted area is not the reason I became more healthy". The former doesn't eliminate the possibility that eating better could still be the only reason for him being healthier whereas the latter eliminates that possibility -- thus, needs to be assumed! Thank you sooo much Noah!!!!!!