Q15 - The Scorpio Miser with its

[ptraye]

What is the flaw in this stimulus? I could not identify the type of flaw being presented here?

And, how does it relate to the answer choices?

[timmydoeslsat]

So if it is true that the Miser costs more than the standard, and it would take 60,000 miles of driving to achieve a break-even point, does it follow that a lower cost of fuel would help get to that break-even point quicker?

It actually would take longer if the cost of fuel is less. The more fuel costs, the quicker it would take, as this is how the Miser makes up ground with its fuel efficiency.

Same holds true with C. The wage factor is how the Roadmaster is exceptional. Low wages make this factor less advantageous.

[demetri.blaisdell]

Good work on this question. The flaw on this one is somewhere between a flaw in reasoning and a flaw in math. Let me try to explain it again so you can see it one more time:

If it costs $50 to fill up your tank:

Scorpio Miser (high-efficiency) costs $5,000/year in gas to run.
Standard Scorpio costs $10,000/year.
So, the savings is $5,000/year if you buy the Miser.

Price of gas drops so now it only costs $25 to fill up your tank:

Scorpio Miser (high-efficiency) costs $2,500/year in gas to run.
Standard Scorpio costs $5,000/year.
Now, the savings is only $2,500/year if you buy the Miser. Because you are saving half as much money per year, it will take longer to make up the difference.

(C) has the same problem. The city plans to make up the difference between the Roadmaker (expensive machine) and the cheaper machine by hiring less workers. They plan to save money over time just like above. But if the cost of labor is low, you won't be saving very much. It would be better to just buy the cheaper machine and hire cheap laborers. But (C) says with low labor costs, it's better to buy the Roadmaker. That's backwards.

I hope seeing this again helps. Let me know if you have any questions.

Demetri

[Mab6q]

Can anyone explain why the other choices, particularly B, are incorrect?

[ohthatpatrick]

Let's remind ourselves what we're looking for:

i. Some situation that has a mathematical relationship (see Demetri's post above!)
ii. A conclusion in which the author concludes the OPPOSITE of the correct mathematical relationship

Correct answer C gives us this math:
Roadmaker is faster. Competing model is cheaper.
Roadmaker lets you work with fewer people, so the reduced staffing costs balances out the higher price.
Therefore, Roadmaker is particularly advantageous when wages are low.
But that's the opposite of what's true. It's most advantageous when wages are high, because each person no longer on the job results in bigger savings.

(A) This is valid math. The original equation is
True rate = Interest rate - Inflation rate

And the conclusion is saying,
True rate = (Interest rate - x) - (Inflation rate - x)

That's valid.

(B) This is also valid math. The original relationship is that when you buy a Polar freezer, you SPEND more money on electricity, but you MAKE more money on premium foods. (So the more money you spend on electricity, the more premium foods you need to sell to balance that out)

And the conclusion is saying, the less you spend on electricity, the less premium food you need to sell to balance that out.

(D) This answer is not worth reading/thinking about since the conclusion doesn't match the original at all. There's no mathematical relationship to look at in the conclusion. It's just a prescriptive "should" statement. The argument is definitely flawed: the author assumes that the new strain does not have any disadvantages that would outweigh its advantages. But it's not a math flaw.

(E) Same problem as (D): the conclusion is a prescriptive "should" statement, not a math claim. This is also a valid argument. Bonds remain constant; stocks vary. Thus, if you want stability, you'd choose bonds over stocks.

Hope this helps.

#officialexplanation

[economienda]

What I do with these type of questions is try to match the last sentence of the stimulus to the last sentence of the answer choices. Is this a bad technique?

[tommywallach]

Yes, that's a bad idea. Questions regularly switch up the order in which sentences are delivered (from a structural standpoint) between the answer choices and/or stimulus, so that wouldn't be inherently safe.

[MeenaV936]

What is the difference in the fundamental way you're supposed to approach Match the Reasoning questions vs. Match the Flaw questions (like this one)? I tend to do them the same way -- look for similar rhetoric in the stimulus and answer choices (ex) words like "likely," prescriptive statements, etc) and then match them up. Is this the right approach? What approach should I be taking for each?

[ohthatpatrick]

The approach you're referring to is a good Plan B for Match the Flaw, whereas it's Plan A for Match the Reasoning.

For Match the Flaw, your #1 job should be to figure out:
What's the flaw?

We don't have that job on Match the Reasoning, because 99% of them are valid / reasonable arguments.

When we have a hard time naming / articulating / finding the flaw on Match the Flaw, we can often still get the question right by attending to structural features. But the correct answer doesn't HAVE to match all the structural features (it just usually does). It only has to commit the same type of flaw or be vulnerable to a similar type of objection.

So the fundamental difference is this:

MATCH THE REASONING:
1. What are the structural qualities of this argument? (how many premises? how are they combined? what is the type and the strength of each premise and of the conclusion?)


MATCH THE FLAW:
1. What's the flaw in this original argument?
(2. What are the structural qualities?)

Hope this helps.