Q17 - Certain instruments used in veterinary

[stackoutawinner]

I just spent 8 minutes going over this problem to really understand it.

I would classify this question as an inference question - there's no conclusion. They give us 5 conclusions and tell us that 4 could be true, except one.

Here's the problem I've had here... the four wrong answers all "could" be true under various situations and the right answer MUST be true - I was looking for a must be false type of choice, but perhaps I'm mistaken in how I've read the choices?

Here's how I have it lined up thus far:
1. 50n = 3.4x(n)
2. 50s = 2.1x(s)

Because there's no conclusion on the observed data, and because there's missing information (most notably total energy - these only give us relative energy), we cannot accurately conclude anything between the two data sets and must only look to see what's possible.

Answer choice A could be true, for example, if the energy of production was the same in the two sets.

Answer choice C could be true if the two set sizes were not equal. In other words, a set of nylon tools contains more tools than a set of steel tools.

Answer choice D could be true especially if the energy to sterilize each set was equal - under this could be situation, the steel would have to cost more to produce.

Answer choice E could be true because cost is different than the energy used. The cost would include such factors as material and labor or manufacturing capital. If these costs were cheap, then it's certainly possible and there's nothing prohibiting it.

Answer choice B, the one I skipped, restates the first observation of 50n = 3.4x(n) where x is the amount of energy used in production. The 3.4 clearly dictates that it took 3.4 times the amount of production energy to sterilize. Sterilizing MUST be more energy intensive than producing on a marginal basis.

Did I misunderstand answer choice B, or did the LSAT authors split hairs on this question? I mean, yes, technically the answer MUST be true and therefore is not in the "could" be true realm, but my goodness - what kind of crap question does that?

If I'm correct, can one of the Atlas text authors (ie, Mike or Dan) give me an idea of how often such a thing could be expected?

Thanks!

[dan]

Hey Stacks. You've got the right idea, but your math is a little shaky. Answer B actually must be false, which is an answer that makes more sense given the question: Each could be true EXCEPT (we want one that must be false).

Here's an explanation:

Question type: Inference
This is an infernce question, but it’s worded differently than most. In this case, four of the choices could be true in some hypothetical case but one answer choice (the one we want) CANNOT be true. We’re looking to use the text to prove one answer false.

Let’s define some variables:

nm = energy required to manufacture nylon instruments
ns = energy required to sterilize nylon instruments once

The text says that sterilizing the nylon instruments 50 times used 3.4 times the amount of energy that was required to manufacture them:

50(ns) = 3.4(nm)

If this is the case, then the amount of energy required to sterilize the nylon instruments once, ns, must be SMALLER than the amount of energy used to manufacture those instruments. Here it is mathematically (divide both sides by 50):

ns = (3.4/50) nm

ns is a small fraction of nm. Answer (B) must be false. Because we know something about the ratio of energies used to manufacture vs. sterilize the nylon instruments, we can draw a conclusion about which must be smaller.

(A) is incorrect. We know nothing about the raw amounts of energy used for the sterilizations of steel and nylon, and thus we can’t compare them. This may or may not be true.
(C) is incorrect. We know nothing about the number of instruments. This may or may not be true.
(D) is incorrect. We know nothing about the raw amounts of energy used for the manufacturing of steel and nylon instruments, and thus we can’t compare them. So, this may or may not be true.
(E) is incorrect. We know nothing about the cost of sterilization. This may or may not be true.

Hope this helps.
dan

[stackoutawinner]

Thanks!

And might I add... "doh!"

[soyeonjeon]

Since it states that 50 complete sterilizations of a set fo nylon instruments required 3.4 times the amount of energy used to manufacture "that set of instruments",
shouldn't it be
ns * 50 = mn * 3.4 * 50
? Doesn't "that set of instruments" mean 50?

How are we supposed to know whether "that set of instruments" indicate 1 or 50 ? Is it because set is singular that we know it to be one set rather than 50 sets?
I'm lost on this sets or set.
Thank you.

Thank you.

[chyne510]

The explanations are great on this. Is it possible to have someone from Manhattan fully explain this problem from beginning to end.

[tommywallach]

Dan's an instructor! : )

-t

[economienda]

They key phrase in (B) is: "each complete sterilization" which means 1 sterilization (or 1 of the 50 complete sterilizations).

So more energy was required for the 50 sterilizations than was required to manufacture the nylon set; but,

it must be FALSE that: More energy was required for 1 sterilization than was required to manufacture the nylon set, which is what (B) says.

[josh.randall52]

I get why B is right. Reading the question during drilling, I was a little confused by the wording, "required for each complete sterilization". I'm assuming that means one sterilization of the 50 total sterilization, hence why it has to be false.

[Jmaksimiuk]

Hey,

I was wondering if someone could explain why C is wrong to me. This is the answer that I originally picked.

While I now understand why B is correct, I still can't figure out why C is wrong. The way that the stem is worded, it implies that both sets of instruments are the same. It says: "Certain instruments used in veterinary surgery.." Then the second sentence continues with: "In a study of SUCH instruments...". Is it valid to assume that they mean the same set of instruments for both? Thanks in advance for any answers!