Lesson: Assumption Questions

Comment on Assumption Questions

Hey! Is C the answer for the first 500 to 650 question (utility companies presupposes..)?
gmat-admin's picture

You're referring to http://gmatclub.com/forum/in-response-to-the-increasing-cost-of-producin...
Yes, the correct answer is C.
Just click on the "Reveal Spoiler" link to view the correct answer.

Hi Bret,

Thank you! I dont see your detailed answer for the above question. Thank you for your help in advance.
All the best
Fatima-Zahra
gmat-admin's picture

Hey!

Totally lost with the third 650-800 question? No convincing answers on the gmatclub.

http://gmatclub.com/forum/the-average-hourly-wage-of-television-assemblers-in-vernland-24622.html
gmat-admin's picture

Hey! I just answered that question: http://gmatclub.com/forum/the-average-hourly-wage-of-television-assemble...

Cheers,
Brent

Hi Brent,

Thank you for these amazing lessons.

I still have difficulties with 650-800 questions. I would like to practice more. Grateful if you could advise where I can find practice question of this type.

Thanks a lot

Fatima-Zahra
gmat-admin's picture

GMAT Club has a searchable database (here: https://gmatclub.com/forum/search.php?view=search_tags) with thousands of official questions.

Hi Brent,

In Assumption CR Q's, how do i eliminate the answers to get the write answer?
I've tried everything from negation to elimination by writing the conclusion and premise down to find the right assumption.

Please help me! I seem to get most CR question's wrong.
gmat-admin's picture

Hi shefali,

It sounds like you have the correct strategies, so it's hard to say what the issue is.

You might want to take your time reviewing multiple responses to each question to get a better feel for this question type.

I hope that helps.

lol, I'm assuming that i don't die before i take my GMAT exam next month.
gmat-admin's picture

Ha, that is definitely an important assumption. Now let's see what happens when we apply the negation technique to this assumption .... :-)

Hi Brent- can you explain meaning of choice "C", my understanding is that it says children having allergic reaction are not sent to nurse, if this is case then how is it right ans?

https://gmatclub.com/forum/exposure-to-certain-chemicals-commonly-used-in-elementary-schools-28474.html
gmat-admin's picture

Question link: https://gmatclub.com/forum/exposure-to-certain-chemicals-commonly-used-i...

The passage tells us that more kids exposed to the chemicals are being sent to the school nurses

The conclusion is that EITHER Renston's schoolchildren have been exposed to greater quantities of the chemicals OR the children are more sensitive to them than schoolchildren were ten years ago.

In other words, the author is saying that there are only two possible things CAUSING the increase of kids sent to the nurse:

#1) the kids are getting exposed to greater quantities of the chemicals

#2) the kids are becoming more sensitive to the chemicals

When we NEGATE answer choice C, we get:

Children who have allergic reactions to the chemicals ARE more likely to be sent to a school nurse now than they were ten years ago.

This negated answer choice DESTROYS the argument, since it says that the CAUSE of the increased nurse visits is something OTHER THAN #1 or #2.

Does that help?

Thanks

Hi Brent, what would be the answer here. Everyone is eliminating E, but I feel its the only one that targets the reduction in "number of truckloads".

https://gmatclub.com/forum/last-year-all-refuse-collected-by-shelbyville-city-services-was-incine-9971.html

gmat-admin's picture

The city (by recycling) hopes to reduce the number of truckloads of refuse TO BE INCINERATED to half of last year's number. This, in turn, will decrease the amount of ash generated this year to half of last year's amount.

Answer choice E does not specifically talk about the number of truckloads of refuse TO BE INCINERATED; it talks about the TOTAL quantity of refuse collected.

The TOTAL quantity of refuse collected = (quantity of recyclable refuse) + (quantity of refuse TO BE INCINERATED)

When we NEGATE E, we get: The TOTAL quantity of refuse collected by Shelbyville city services this year WILL BE greater than that collected last year.

This negated premise does not destroy the original conclusion, because more total refuse does not necessarily mean more refuse to be incinerated. The total amount of refuse might be 99% recyclables, in which case, the city will still meet its goal of halving the quantity of ash generated.

Now let's NEGATE answer choice D (the correct answer).

We get: The refuse incinerated this year will generate MORE residual ash per truckload incinerated than did the refuse incinerated last year.

So, a 50% reduction in the quantity of refuse TO BE INCINERATED will not translate into a 50% reduction in the quantity of ash.
This negated premise DESTROYS the conclusion. So, D must be correct.

Dear Brent,
When you say identify and summarise the conclusion / premises, do you mean we do so mentally or to jot it down in our pad?
gmat-admin's picture

Good question.

If you can create super concise summaries, then I think the process of writing them on your scratch paper can be very beneficial.

That said, you might want to experiment to see whether jotting them down helps.

Cheers,
Brent

Hi Brent!,

Regarding question 550 (2018 official guide), what do you think about the given explanation in answer B). That means that if in any other question a ranking is mentioned as an explanation, we should distrust it?

Thanks in advance for your help!
gmat-admin's picture

Question link: https://gmatclub.com/forum/political-theorist-even-with-the-best-spies-a...

When we read answer choice B, the part that says "leaders whose foreign policy decisions have been highly RANKED..." should stand out.
Why not just say "leaders whose foreign policy decisions ARE good..."?
The addition of this "ranked" proviso makes this answer choice considerably weaker.

Also, answer choice B does not address the part about making decisions when "information is incomplete," whereas answer choice E DOES address that.

For these reasons, I think E is a little better than B.

YOUR QUESTION: If, in any other question, a ranking is mentioned as an explanation, we should distrust it?

Although I'm reluctant to provide a sweeping rule/guideline, I can say that I've seen CR passages in which the author cites an authority (like a study or a scholar) as the major reason for drawing a particular conclusion. In these cases, we should definitely be wary of this argumentative strategy.

https://gmatclub.com/forum/700-country-b-s-oil-production-is-not-sufficient-to-meet-196647.html
why not option e sir?
gmat-admin's picture

Question link: https://gmatclub.com/forum/700-country-b-s-oil-production-is-not-suffici...

I'm not a huge fan of this question (I suggest that students stick with the 1000's of official practice questions out there).

Let's try the negation technique on E.

We get: It is NOT the case that ethanol is as efficient as gasoline in terms of mileage per gallon when used as fuel for automobiles.

Does this DESTROY the argument that Country B will succeed in its plan to reduce its dependence on foreign oil?
Maybe, maybe not.

The passage tells us that, combined with its oil production, Country B produces enough ethanol from agricultural by-products to meet its current demand for energy.

If it's the case that ethanol is 99% as efficient as gasoline, AND Country B produces 20 times the amount of ethanol needed to meet its needs, then the negated assumption does NOT destroy the conclusion.

Conversely, if it's the case that ethanol is only 5% as efficient as gasoline, AND Country B produces BARELY enough ethanol needed to meet its needs, then the negated assumption DOES destroy the conclusion.

On the other hand, answer choice D, when negated, does destroy the conclusion.

Cheers,
Brent

Hi Brent,

Could you please post a detailed explanation for below Q, explaining the logic used behind identification of the Q as an Assumption Q and using the Negation technique on the answer choices.

Link : https://gmatclub.com/forum/a-significant-number-of-unitron-corporation-s-department-heads-are-due-222367.html

Thanks & Regards,
Abhirup
gmat-admin's picture

Hi Brent,

Please refer Q : https://gmatclub.com/forum/q14-the-milk-of-many-mammals-contains-cannabinoids-20899-20.html

I applied Negation technique to (B) : Cannabinoids are NOT the only substance that stimulates the appetite. There are other substances as well that stimulate. If that is the case then the conclusion,Cannabinoids probably function to stimulate appetite, doesn't hold any longer. Since the Negated assumption breaks the Conclusion I figured (B) could be the correct choice. Could you please explain whats wrong?

Thanks & Regards,
Abhirup
gmat-admin's picture

Question link: https://gmatclub.com/forum/q14-the-milk-of-many-mammals-contains-cannabi...

Be careful. IF the conclusion were "cannabinoids are the ONLY substances that stimulate the appetite," then the negation of answer choice B would kill the argument. However, there could be many things that stimulate appetite.

Here's an example:
Whenever Joe runs a marathon, he sweats a lot. Therefore, running marathons makes Joe sweat.
Which of the following is an assumption that's required?

A) Running is the only activity that makes Joe sweat.
Is this a required assumption?
No.

Does that help?

Cheers,
Brent

1. If the conclusion were "cannabinoids are the ONLY substances that stimulate the appetite," then would answer choice (B) have been correct.

2. Can we say that (B) would have been a correct option in a Strengthen Q with same stimuli as the one mentioned in Q Link : https://gmatclub.com/forum/q14-the-milk-of-many-mammals-contains-cannabinoids-20899.html ? Its good to have but not necessary.
gmat-admin's picture

1. Yes, B would be correct.

2. Tough one. Yes, I'd say that B would help strengthen the argument.

Cheers,
Brent

Thanks Brent!!

I am ltonser. I need help. What can i do it?
gmat-admin's picture

Hi ltonser,

I think you need to be more specific. What do you need help with?

Cheers,
Brent

https://gmatclub.com/forum/commentator-in-the-new-century-only-nations-with-all-the-latest-286291.html
please explain.
gmat-admin's picture

https://gmatclub.com/forum/archaeologist-the-mosaics-that-were-removed-from-zeugma-the-ancient-289877.html
sir though I was able to get the correct answer by eliminating rest I don't know how a is the assumption
gmat-admin's picture

Question link: https://gmatclub.com/forum/archaeologist-the-mosaics-that-were-removed-f...

The wording of this question is atypical for the GMAT (it's an LSAT question after all :-).
I'd say that it's more of a STRENGTHEN the argument question.

The argument suggests that the mosaics should have been left where they were, because their absence may confuse future archaeologists.
So, the conclusion is based solely on archaeological reasons.

If we NEGATE answer choice A, we get: There are NON-archaeological reasons that should be considered.
This seriously undermines the argument.

Cheers,
Brent

A proposed change to federal income tax laws would eliminate deductions from taxable income for donations a taxpayer has made to charitable and educational institutions. If this change were adopted, wealthy individuals would no longer be permitted such deductions. Therefore, many charitable and institutions would have to reduce services, and some would have to close their doors.
The argument above assumes which of the following?
(A) Without incentives offered by federal income tax laws, at least some wealthy individuals would not donate as much money to charitable and educational institutions as they otherwise would have.
(B) Money contributed by individuals who make their donations because of provisions in the federal tax laws provides the only source of funding for many charitable and educational institutions.
(C) The primary reason for not adopting the proposed change in the federal income tax laws cited above is to protect wealthy individuals from having to pay higher taxes.
(D) Wealthy individuals who donate money to charitable and educational institutions are the only individuals who donate money to such institutions.
(E) Income tax laws should be changed to make donations to charitable and educational institutions the only permissible deductions from taxable income.
hello, sir
why B is wrong here?
gmat-admin's picture

CONCLUSION: Without the tax incentives, many charitable/educational institutions will suffer.

Let's apply the NEGATION technique to A and B.

A) If we NEGATE answer choice A, we get: Without incentives offered by federal income tax laws, ZERO wealthy individuals would not donate as much money to charitable and educational institutions as they otherwise would have.

In other words, even without the tax incentives, all wealthy people will donate the same amount as before.
This certainly harms the conclusion.

B) If we NEGATE answer choice B, we get: Money contributed by people who donations because of tax incentives ARE NOT the only source of funding for many charitable and educational institutions.

This does not harm the conclusion. The negated answer choice B says that there are sources of funding beyond those who donate solely because of tax incentives. S, if there are other sources of funding, it need not be the case that some charitable institutions will suffer.

Does that help?

Cheers,
Brent

Hi Brent, There is one question doubled in the question list below the video, the one about the average hourly wage of television assemblers in Vernland and Borodia. Cheers. Love your work. Alex
gmat-admin's picture

Hi Alex,

Thanks for the heads up and for the kind words!
I've deleted one of the questions.

Cheers,
Brent

Help. I am looking for guide
gmat-admin's picture

Are you referring to the Official Guide for GMAT Review?
If so, here's the latest copy: https://www.amazon.com/dp/1119576067
You can also find a copy here: https://gmatclub.com/forum/gmac-official-guides-the-master-directory-lin...

Proposed new safety rules for the Beach City airport would lengthen considerably the minimum time between takeoffs from the airport. In consequence, the airport would be able to accommodate 10 percent fewer flights than currently use the airport daily. The city’s operating budget depends heavily on taxes generated by tourist spending, and most of the tourists come by plane. Therefore, the proposed new safety rules, if adopted, will reduce the revenue available for the operating budget.

The argument depends on assuming which of the following?

(A) There are no periods of the day during which the interval between flights taking off from the airport is significantly greater than the currently allowed.

(E) The response to the adoption of the new safety rules would not include an increase in the number of passengers per flight.
-------------------------------------------------------------------------------------------------------------------------------------------
A: [Necessary assumption] The author isn't considering any other possibilities that may cause delay in takeoff of flights other than Safety Rules, such as weather, etc. -> Clearly perfect bcuz deals with time, another cause of delay and also tourists' number being affected.

E: Re-stated as it is: [Passengers / flight Could also fluctuate in the case without the Safety Rules as Seats per flight ain't our concern. Could also be a case that they miss flight or don't book at all.].
gmat-admin's picture

PREMISE: The proposed rule will reduce the number of flights by 10%.
PREMISE: The city needs tax money from tourists arriving by plane
CONCLUSION: New rule will reduce tax money

Let's NEGATE each premise...

A) There ARE periods of the day during which the interval between flights taking off from the airport is significantly greater than the currently allowed.
So, the rule will not affect the number of tourists during those periods of the day.
HOWEVER, the airport will still see a 10% reduction in flights, which will still reduce the number of tourists, which will still reduce the amount of tax money the city receives.
The negated premise does not seem to weaken the conclusion.

(E) The response to the adoption of the new safety rules WILL include an increase in the number of passengers per flight.
So, even though there will be 10% fewer flights, the flights that do arrive will be carrying MORE PASSENGERS.
So, the city may not lose the tax revenue from tourists arriving by plane.
The negated premise DOES seem to weaken the conclusion.

Best answer: E

Does that help?

Cheers,
Brent

Yes it helps somewhat, although both choices were too eligible at first glance.

In Wareland last year, 16 percent of licensed drivers under 21 and 11 percent of drivers ages 21-24 were in serious accidents. By contrast, only 3 percent of licensed drivers 65 and older were involved in serious accidents. These figures clearly show that the greater experience and developed habits of caution possessed by drivers in the 65-and-older group make them far safer behind the wheel than the younger drivers are.

Which of the following is an assumption on which the argument depends?

(A) Drivers 65 and older do not, on average, drive very many fewer miles per year than drivers 24 and younger.
My REASON: Eligible-Keep

(B) Drivers 65 and older do not constitute a significantly larger percentage of licensed drivers in Wareland than drivers ages 18-24 do.
My REASON: Argument Type - Statistical. Prove the Percentage wrong just as we did in More Retired US citizens are moving to other states of US. Florida now has lesser percentage of Citizens settling in than 10 yrs before. Link: https://gmatclub.com/forum/topic136004.html

(D) The difference between the accident rate of drivers under 21 and of those ages 21-24 is attributable to the greater driving experience of those in the older group.
My REASONINGS:
1. Assumption is a Necessary info required to link Premise & Conclusion. ---> It was not a necessary info at all, as we already had it as Conclusion.
2. Also, if we see Option D has restated the Conclusion instead of elaborating/supporting an existing premise. ---> I want to know if an option restates a Conclusion then - Is it always wrong? - because it didn't restate the premise, which is correct way of restating.
3. I believed option D to be wosrt answer of all 3 options.

I chose B after all assuming it to Prove the statistics wrong.
gmat-admin's picture

Question link: https://gmatclub.com/forum/in-wareland-last-year-16-percent-of-licensed-...

For answer choice B (your choice), how does the passage from https://gmatclub.com/forum/in-the-united-states-of-the-people-who-moved-... help you "prove the statistics wrong?"

For assumption questions, the Negation Technique is the best way to analyze answer choices.

If we negate (A), we get: Drivers 65 and older DO, on average, drive very many fewer miles per year than drivers 24 and younger.
If the seniors are not driving much (due to not having jobs, poor health, etc), then the lower accident rate is caused by lack of driving; it's not caused by seniors by being safer drivers. This seriously harms the original conclusion.

If we negate (B), we get: Drivers 65 and older DO constitute a significantly larger percentage of licensed drivers in Wareland than drivers ages 18-24 do.
So, there are many more senior drivers than there are younger drivers.
Does this hurt the original conclusion?
No. The argument concerns accident RATES, and the size of the population does not affect RATES.

Does that help?

Cheers,
Brent

https://gmatclub.com/forum/technically-a-given-category-of-insurance-policy-is-under-priced-if-77000.html

Why is the answer E? The conclusion is that the loss incurred is compensated as the premium income is invested and thus profit is earned.
I think ans is D.

Hello sir
Im getting stuck with two options in most of the questions like the one below. How do I overcome this issue?
https://gmatclub.com/forum/commentator-the-theory-of-trade-retaliation-states-that-countries-clo-7864.html
Got stuck between A and D.

Pages

Office Hours

On December 20, 2023, Brent will stop offering office hours. 

Change Playback Speed

You have the option of watching the videos at various speeds (25% faster, 50% faster, etc). To change the playback speed, click the settings icon on the right side of the video status bar.

Have a question about this video?

Post your question in the Comment section below, and a GMAT expert will answer it as fast as humanly possible.

Free “Question of the Day” emails!