Fast-food restaurants make up 45 percent of all restaurants in Cantari

Fast-food restaurants make up 45 percent of all restaurants in Cantaria. Customers at these restaurants tend to be young; in fact, studies have shown that the older people get, the less likely they are to eat in fast-food restaurants. Since the average age of the Canatrian population is gradually rising and will continue to do so, the number of fast-food restaurants is likely to decrease.

Which of the following, if true, most seriously weakens the argument?

Argument = Older people eat less at fast food restaurants + Avg Canatria age increasing -> # fast food goes down

(A) Fast-food restaurants in Canatria are getting bigger, so each one can serve more customers. out of scope; if anything this strengthens conclusion (more ppl can fit in a restaurant, less restaurants are needed )

(B) Some older people eat at fast-food restaurants more frequently than the average young person. this one is tricky! makes it seem like bc there's older people that eat at restaurants more frequently than the avg young person, it contradicts a premise BUT you have to remember this doesn't mean that the AVG old person doesn't eat as frequently as the AVG young person, just like there can be genius high schoolers smarter than the avg college student but it doesn't mean the avg high school student is smarter than the avg college student

(C) Many people who rarely eat in fast-food restaurants nevertheless eat regularly in restaurants. out of scope

(D) The overall population of Canatria is growing steadily. even if the avg age goes down, if there's same or more young people than the amt of restaurants may not go down

(E) As the population of Canatria gets older, more people are eating at home. wrong, if anything this strengthens. more old people eating at home -> less fast food restaurants

VeritasKarishma

if in option b All is mentioned instead of some will then optin is correct

like in this question it's not 100 % full proof weaken ans
i have seen many questions like the same which aren't 100% proof ans in strenthen and weaken type. So should i look for options which just provide belief of either strengthening or weakening

Any other insights you wants to give regarding this type of answers

If (B) has "all" in place of "some", it will negate this premise:
"studies have shown that the older people get, the less likely they are to eat in fast-food restaurants"

We need to take the premises to be true. It doesn't make sense then to have its negation true too.

When can the average age of a population rise and continues to rise?
Few possibilities are:
- When there are no deaths at older ages and no new born babies - Steady population
- When the number of people moving to old age is greater than the number of newly born - Growing population
- When the population comprises of only young people and nobody dies - Steady population
- When the number of newly born are more than the total age of people growing older/total age of people dying - Growing population

The assumption in the question is that the just because the average age of the population is rising, there would be only older people in the population as a whole. We can see that the author has ignored other possible scenarios.

Which of the following, if true, most seriously weakens the argument?

(A) Fast-food restaurants in Canatria are getting bigger, so each one can serve more customers. - The reason for decrease in fast-food restaurant is attributed to the fact that there would be older people in the population. The fact that fast food restaurants in Canatria are getting bigger and can serve more customers has no impact on the conclusion. A definite Loser!

(B) Some older people eat at fast-food restaurants more frequently than the average young person - The eating pattern/frequency of older people is introducing another variable in the analysis. The variable we need to analyze are 'average increase in the population' resulting to 'decrease in the fast food restaurants' - Loser

(C) Many people who rarely eat in fast-food restaurants nevertheless eat regularly in restaurants - Many people? Who are these people? How does the fact that they rarely eat in fast-food restaurants while eat regularly in restaurants affect the author's reasoning around that the average age increase would result in decrease in fast-food restaurants in the future? It does not! Loser

(D) The overall population of Canatria is growing steadily - If we consider the last case mentioned above, then the growing population is actually resulting in more new borns, thus more young people in the times to come. It does give us a reason to doubt the relationship between the average age rise and the decrease in the fast-food restaurants - Contender and Winner

(E) As the population of Canatria gets older, more people are eating at home - No relation to the argument!

A few Kudos would help

You can’t argue with the facts given.

Any answer choice that “appears” to undermine the premises will never be a true weakener. I say “appears”, because they don’t ever really undermine the facts.

You can have a majority of the old ppl not likely to visit the rest., while still having SOME who continue to do so.

The question is, does the author’s conclusion still follow from all the facts laid out? Have we in some way made it less likely that he is correct?

Not really, because he never said ALL old ppl avoid fast food restaurants.


However, the author is concluding that because the AVERAGE age of the population is growing and MOST of these older ppl are LESS LIKELY to visit these rest., they will not have enough customers and go out of business


The author is basing this conclusion on an average age steadily rising. What if the overall population increases and we have a lot more younger ppl, even though the older ppl are still more?

This means the rest. will still have enough younger customers who are more likely to eat there

Simple and extreme numbers.

Right now there is 100 young ppl and 40 old ppl. The rest. needs 40 customers to survive. It’s getting a lot of young ppl and maybe a few older so it’s doing fine.


The average age of the population has now aged. But, as the correct answer now tells us, the overall population has also increased.

We now have 400 young ppl and 10,000 old ppl. The rest still only needs its 40 customers to survive. So they will likely be ok in contrast to the author’s conclusion.

Posted from my mobile device

I rejected option D on the grounds that "population increase" could also be due to people moving to this city and there could be a possibility that majority of these people moving into the city could be old people(?) Due to this ambiguity I Went for option B which i wasn't also a fan of. Can someone tell me why it would be incorrect to think like this?

We posted an explanation of why answer choice (B) is incorrect here and an explanation of why answer choice (D) is correct here. Let us know if those don't clear things up!

Hi GMATNinja - wanted to go over your statement in the yellow highlight. Mentioned in the yellow with regards to D -- there are some scenario that weaken and some scenario's that don't weaken when it comes to option D

Hence option D should not automatically be eliminated.

But according to this logic, even then there are scenario's in option B which weaken

--In option B, word -- the word "Some" can mean everything from 1 % to 30 % to 49 % to all 100 % of the people. That is the clinical definition of the word "some" (anything but zero)

So option B -- there are scenario's where perhaps option B is referring to 20 % or 30 % or 49 % of the elderly that order more frequently that young folks (it cannot be 50 % or more as that would be go against the premise)

Hence in this specific scenario's (20 % or 30 % or 49 %) option B -- you would agree , option B would also weaken the argument by a little bit.

Just wondering what your thoughts are on something like this !

Thank you for everything !

If "overall population" implies all aged groups, yes then it makes sense, but I perceived overall population as an entire population of that city. If you apply my perception, if significant increase is due to influx of old people, then option does not hold water. It would have been nice if there was more elaboration on overall population. Many people use overall population and entire population interchangeably.

Great question! Even if it's true that some older people eat at fast-food restaurants more than the average young person does, this doesn't affect the fact given in the argument that the older you get, the less fast food you eat. So in the future, as the population gets older, people will eat less fast-food -- even if there are some old people who still eat more fast food than all the teenagers.

If you want to think about it a bit more quantitatively, the argument is telling us that there's a distribution for young people and another distribution for old people and that the mean for old people is lower than the mean for young people. Answer choice (B) is telling us that the standard deviation for old people is high because there are some old people who eat more than the average young person (and therefore a whole lot more than the average old person). But if we're concerned with the total demand for fast-food, we only care about the mean for each distribution and how many people are in each group (because mean consumption will equal total consumption divided by n). The standard deviation doesn't matter.

I hope this helps!

I mean yeah..i get D - but who cares if the overall population is growing if the average age is still rising?
If the overall average age rises, the overall customer base in relation to the average continues to worsen. How exactly does the "weaken" the argument?

At least B suggests that some old people eat at rates HIGHER than younger people. And if the population continues to get older, maybe this same population of older people will eat at higher rates.

In this Weaken problem, the right answer will make the conclusion less likely to be true. In this case, the right answer will show that the number of fast food restaurants in Canatria may not decrease in the future. Either there will be more fast food customers than expected or a decline in the number of customers will not cause a decline in the number of restaurants. Options D says overall population of Cantaria is increasing. So the it is expected customer will increase in coming days and the restaurant will not have to close its business.

The answer is D.

Hi GMATNinja - Thank you for following up.

Was reviewing your response in the yellow and I think I bit off more than what I can chew. I am not able to visualize what you are saying in the yellow unfortunately.

Focussing on the purple specifically

- Are you saying, that even if the word "Some" in option B is referring to a % as high as 49 % - that still does not weaken the argument ?

Are you saying that the reason that it STILL does not weaken the argument is :
-- 49 % of the elderly go to Fast food chains more frequently but perhaps order just a small coffee

Even if 49 % of the elderly go to McDonald's more frequently, it doesn't necessarily mean they will order large meals ?

I suppose another variable about frequency of visits vs average order size exists (though the argument per my understanding does not necessarily state that the "Total fast food consumption" by the young > total fast food consumption)

Feel free to correct me if i am wrong

Thank you !

Hi VeritasKarishma - what if option B had "49 % of the older people eat at fast food restaurants more frequently than the average young person"

Would that weaken in your view ?

Initially I thought it would weaken but now I am thinking , even if the percentage is 49 % or 100 %, it may not go against the premise

""studies have shown that the older people get, the less likely they are to eat in fast-food restaurants"

because it quite possible that 49 % or 100 % of the elderly just frequent fast food restaurants and it's quite possible they just order a coffee (1 $ value) whereas the young may frequent less and order on average 15 $ worth of food perhaps

Thoughts on if (B) was 100 % or 49 % instead of 'Some" -- would that still not weaken or would that weaken ?

Thank you !

Thank you !

Given premise:
"studies have shown that the older people get, the less likely they are to eat in fast-food restaurants. "

So people at 40 yrs of age eat less frequently in fast food restaurants than do people at 20 yrs of age. Either a smaller fraction of 40 yr olds may be eating in these restaurants or all may be eating but less frequently than 20 yr olds.
Even if 100% 40 yr olds eat at fast food restaurants, they may be doing so only once a month while 20 yr olds may be eating there every week.

Option (B) says that "some" older people eat more frequently than do youngsters so they are giving "some" as the exception group to the rule that older people are less likely to eat. Had this been "all older people eat more frequently than do youngsters," that would make the premise false. So an option like that would be unacceptable.

The distinction is not between 'eat' and 'visit'. The argument as well as the option (B) talks about 'eat'.

Hi VeritasKarishma - Just one last follow-up

If "Some" Was 49 % in option B --it technically will not go against the premise [the premise says "studies have shown that the older people get, the less likely they are to eat in fast-food restaurant, so it could be a razor thin difference technically]

Option B tweaked) Studies have shown that 49 % of the older population eat more frequently than youngsters in fast food restaurants

Would this weaken the argument in your view ?

Why or why not ?
Thank you

There is no evidence to suggest that the inbound population will be any younger than the current population. What if a new retirement village opened up on the island? B or D feel equally specious as potential answers here.