Last August the XT chain of gasoline stations had a temporary sales promotion in effect. In the promotion, any customer who made a purchase of ten or more gallons of gasoline was entitled to a free car wash. For the month of August, XT experienced a ten percent increase in gasoline sales as compared to sales in August the previous year, so evidently the promotion was successful as a means of boosting sales. In evaluating the argument, it would be most helpful to answer which of the following? (A) In the areas in which XT’s gasoline stations operate, how did total combined gasoline sales for all gasoline stations last August compare with sales for the previous August? (B) Was the money that XT earned from the increase in gasoline sales enough to offset the cost of providing free car washes during the promotion? (C) Were there any customers who bought ten or more gallons at an XT gasoline station during the promotion who would have bought gasoline at the same station in lower quantities, but more frequently, if the promotion had not been in effect? (D) Did XT or any of its gasoline stations have to pay other businesses to provide the car washes that customers were offered in the promotion? (E) Are XT’s gasoline sales in August usually significantly higher than one twelfth of XT’s annual gasoline sales?

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Last August the XT chain of gasoline stations had a temporary sales

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KarishmaB

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23 Aug 2024, 04:03

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imhimanshu

Context:
Last August the XT chain of gasoline stations had a temporary sales promotion in effect.
In the promotion, any customer who made a purchase of ten or more gallons of gasoline was entitled to a free car wash.

Premises:
For the month of August, XT experienced a ten percent increase in gasoline sales as compared to sales in August the previous year.

Conclusion:
The promotion was successful as a means of boosting sales.

We need to evaluate whether the increase in sales this year is due to the promotion or some other factor.

(A) In the areas in which XT’s gasoline stations operate, how did total combined gasoline sales for all gasoline stations last August compare with sales for the previous August?

This questions whether the overall gasoline revenue has seen a rise.
If we answer

“Yes” – combined gasoline sales for all stations this time is 10% more than the previous August. Then most gasoline stations would have seen this 10% rise in August sales. Hence the promotion would have had no impact.

“No” – Combined gasoline sales for all stations this time is no more than the previous August. Then we can say with more certainty that the promotion has had an impact.

The two answers affect the conclusion differently. Hence, this is the correct option.

(B) Was the money that XT earned from the increase in gasoline sales enough to offset the cost of providing free car washes during the promotion?

We are talking about sales, not profits. So, whether we made overall profits from the promotion is irrelevant.

(C) Were there any customers who bought ten or more gallons at an XT gasoline station during the promotion who would have bought gasoline at the same station in lower quantities, but more frequently, if the promotion had not been in effect?

The most common incorrect answer.
The station is trying to increase its overall revenue - whether it is through 10 gallons sales or fewer gallons sale is irrelevant. The overall sales has increased.
When we compare customers who bought 10 or more gallons fewer times compared to earlier when they bought the SAME amount of fuel but by visiting more frequently, it doesn't impact the station. These people are today also buying the same amount of fuel that they were buying a year ago. Whether they did it in small amounts or one big, it doesn't impact the success of the promotion at all. What impacts is whether there are people who were not buying at this station or were buying less total amount in the month before but are now buying higher amount. That is what we need to evaluate. That is what will define the success of the promotion.
If we answer

“Yes” – there were some customers who bought 10 gallons in a go due to the promotion but would have bought 2 gallons each on 5 visits without promotion. The promotion did not increase sales in their case. They were buying total 10 gallons and are still buying total 10 gallons. Hence the promotion would have had no impact. It doesn’t help in explaining why 10% increase in gasoline sales was seen with the promotion.

“No” – there were no such customers who bought 10 gallons in a go due to the promotion but would have bought 2 gallons each on 5 visits without promotion. It doesn’t help in explaining why 10% increase in gasoline sales was seen with the promotion.

Both answers affect the conclusion in the same way i.e. they have no effect on the conclusion.

(D) Did XT or any of its gasoline stations have to pay other businesses to provide the car washes that customers were offered in the promotion?

As discussed previously, cost of the promotion is out of scope.

(E) Are XT’s gasoline sales in August usually significantly higher than one twelfth of XT’s annual gasoline sales?

It doesn’t matter how we answer this question. Whether August sales are usually higher than average sales doesn’t matter. We know that this August sales were higher than last August. So the comparison is between the two August months only.

Answer (A)

Discussion on Useful to Evaluate Questions: https://youtu.be/1JtHjH1lWZc

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06 Nov 2024, 07:04

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Honestly the question should have made it clearer that the promotion was run in one particular chain or maybe in not all the chains. Then it would have been easier to ans.

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08 Nov 2024, 15:10

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What do you mean? The opening line specifies that this is about the XT chain in particular. Therefore, when XT sees a boost, we're left wondering whether it's due to something specific to the company, such as this promotion, or to a broader trend. Maybe people just needed more gas this year!

kanikaa9

Honestly the question should have made it clearer that the promotion was run in one particular chain or maybe in not all the chains. Then it would have been easier to ans.

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09 Nov 2024, 03:28

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I am still confused about option A. While I understand comparing combined sales of other gasolines of last year vs this year can give a good picture but there can be too many variables involved. As an example what if -
1)All other gasoline also gave 10% discount seeing this?
2)What if there are new gasoline open this year so combined revenue this year august will be more
3) What if global price of gasoline has gone down so thats the reason for increase of sales.
4)What if there were many gasoline stores that were in renovation last year.
All of these factors can distort the image of this august vs last august sales and we cannot determine for sure if promotion is the reason or not.

Please let me know if I am missing something or wrongly interpreted the option.

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15 Nov 2024, 05:07

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awesome_burst

On assumption-based questions, our goal is never to prove the conclusion correct. It's common for the argument to have multiple flaws, only one of which is addressed in an answer. A is one thing we might want to look at. If overall gas sales are NOT up 10% this year, then it's more plausible that the promotion was helpful, and if they ARE up by 10% or more, then the promotion isn't looking as good. Neither answer would rule out all the other possibilities, but we don't need it to.

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16 Mar 2026, 19:46

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@KarishmaB

I have one doubt regarding the conclustion of the argument: " so evidently the promotion was successful as a means of boosting sales.". Please clarify whether in the conclusion "sales" means sales only in the month of august or overall sales afterwards the promotion. If I assume that in the conclusion "sales" means sales only in august then option C appears to me correct.
Let's assume a hypothetical scenario that there is a customer who buys 2 gallons of gasoline every month. Now because of the promotion if that customer buys 10 gallons in august and does not buy any gasoline for the next 4 months, then in that case it can be said that the promotion has boosted the sale because we are looking into the sale of only August, not of any other month. If there are many customers like this, then those customers can account for the 10% increase in the sale of gasoline. Please tell me where my thought process is wrong.

KarishmaB

Here is the video explanation of this question: https://youtu.be/x6WwaP5PBYc

In the promotion, any customer who made a purchase of ten or more gallons of gasoline was entitled to a free car wash.
For the month of August, XT experienced a ten percent increase in gasoline sales as compared to sales in August the previous year,

Conclusion: the promotion was successful as a means of boosting sales.

Here was the first thing that came to my mind: They are comparing sales in aug this time vs sales in aug last year. That's too much of a time gap. What if this year, the revenue has anyway gone up?
Note that the conclusion is based on "increase in total sales". There is no distinction between transactions of less than 10 gallons and more than 10 gallons.

What would help us evaluate this conclusion?

The only relevant options are (A) and (C) so let's look at them.

(A) In the areas in which XT’s gasoline stations operate, how did total combined gasoline sales for all gasoline stations last August compare with sales for the previous August?

This questions whether the overall gasoline revenue has seen arise this time.
- Say combined gasoline sales for all stations this time is 10% more than the previous August. Then most gasoline stations would have seen this 10% rise in August sales. Hence the promotion would have had no impact.
- Say combined gasoline sales for all stations this time is no more than the previous August. Then we can say with more certainty that the promotion has had impact.
Hence how we answer this question affects our conclusion.

(C) Were there any customers who bought ten or more gallons at an XT gasoline station during the promotion who would have or more gallons at an XT gasoline in lower quantities, but more frequently, if the promotion had not been in effect?

Here is the reason this is not helpful to evaluate. The station is trying to increase its overall revenue - whether it is through 10 gallons sales or fewer gallons sale is immaterial. The overall sales has increased.
When we compare customers who bought 10 or more gallons fewer times compared to earlier when they bought the SAME amount of fuel but by visiting more frequently, it doesn't impact the station. These people are today also buying the same amount of fuel that they were buying a year ago. Whether they did it in small amounts or one big, it doesn't impact the success of the promotion at all. What impacts is whether there are people who were not buying at this station or were buying less total amount in the month before but are now buying higher amount. That is what we need to evaluate. That is what will define the success of the promotion.

Answer (A)

KarishmaB

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17 Mar 2026, 03:14

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Getting fuel for their vehicle is not a once in 6 months activity. More frequently may be weekly while less frequently may be once in 2 weeks or a month. Also we need to find whether the promotion was successful as a means of boosting sales compared to last year. The promotion was run in August and August showed 10% increase in sales. If September showed 10% decrease in sales compared to last year because of the promotion, then there was no boost in sales.
So the question is - did the promotion boost sales? Did it attract more revenue than the station would have otherwise got?
Then whether there were any existing customers who bought in bulk at the promotion or not implies nothing. They got in the same revenue that they would have otherwise got in too. The timing could vary a bit.

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17 Mar 2026, 03:26

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I got your point. You want to mean the sales in the long term, not only of August. Thanks for your clarification.

KarishmaB

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25 Jun 2026, 02:08

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GMATNinja I get it why A is a good choice, but after going through the thread I am not convinced why C should be ruled out?

(C) Were there any customers who bought ten or more gallons at an XT gasoline station during the promotion who would have bought gasoline at the same station in lower quantities, but more frequently, if the promotion had not been in effect?

Yes: there were customer(s) who bought ten or more gallons at an XT gasoline station during the promotion who would have bought gasoline at the same station in lower quantities, but more frequently, if the promotion had not been in effect - weakens the argument that promotion boosted sales.

No: there weren't any customer(s) who bought ten or more gallons at an XT gasoline station during the promotion who would have bought gasoline at the same station in lower quantities, but more frequently, if the promotion had not been in effect - strengthens the argument that promotion boosted sales.

In both cases, assuming that the amount of fuel from 'ten or more gallons' and from 'in lower quantities, but more frequently' is same. Since we get a strengthen and a weaken from C, there is no reason we should eliminate it.

The only thing I see is that it states 'Were there any customers'. If we hone in on any, then we can argue that the mere agreement to presence of atleast one person buying the same higher amount of fuel even in absence of promotion does not necessarily weaken the argument that 'promotion boosted sales'. This is because except for that person, the majority or even all of the rest of customers may only have bought that amount of fuel due to the promotion. Boost in sales is a cumulative phenomenon from the amount of fuel sold to the vast majority or to overall customer base, and cannot be gauged by single person. If this is taken as the case, then yes we do not have a scenario where we can confidently weaken the argument thus ruling out option C.

Please share your thoughts on my approach and if it is 'any' that makes option C incorrect?

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Updated on: 25 Jun 2026, 05:32

Originally posted by Adit_ on 25 Jun 2026, 05:24.
Last edited by Adit_ on 25 Jun 2026, 05:32, edited 1 time in total.

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Actually this is pretty straightforward if done through POE.

If we take B,C,D,E:
C could make sense but if the customers are going to buy frequently anyway they could be matching the number of sales anyway. Knowing the way in which customer buy is not going to prove whether or not the promotion was successful in boosting the sales.

imhimanshu

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25 Jun 2026, 05:27

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I can maybe share my inputs on this.

What does option C say?
Was there a SINGLE customer who did so and so..
Take X lets say:
Let's say he does what option C says.
He buys 11 gallons directly instead of buying 5+5+1.
Does it help say that it boosted sales? NO
He simply ends up buying an equal number of gallons anyway.

I hope this answers why option C is not the right one.

GulfTube

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25 Jun 2026, 06:15

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Last August the XT chain of gasoline stations had a temporary sales promotion in effect. In the promotion, any customer who made a purchase of ten or more gallons of gasoline was entitled to a free car wash. For the month of August, XT experienced a ten percent increase in gasoline sales as compared to sales in August the previous year, so evidently the promotion was successful as a means of boosting sales.

In evaluating the argument, it would be most helpful to answer which of the following?

The argument says XT’s August gasoline sales increased by 10 percent, and concludes that the promotion caused the increase. The key issue is whether XT’s increase was special, or whether gasoline sales in the whole area also increased for some other reason. If all stations had a similar increase, the promotion may not have been the cause.

(A) In the areas in which XT’s gasoline stations operate, how did total combined gasoline sales for all gasoline stations last August compare with sales for the previous August?

This is correct. If total gasoline sales in the area also rose by about 10 percent, then XT’s increase may simply reflect a general market increase. But if other stations did not see a similar increase, then the promotion looks more likely to have boosted XT’s sales.

(B) Was the money that XT earned from the increase in gasoline sales enough to offset the cost of providing free car washes during the promotion?

This is about profit, not sales. The conclusion is that the promotion boosted gasoline sales, not that it increased net profit.

(C) Were there any customers who bought ten or more gallons at an XT gasoline station during the promotion who would have bought gasoline at the same station in lower quantities, but more frequently, if the promotion had not been in effect?

This is not the best question. First, “any customers” is too weak; even if a few customers changed their buying pattern, that would not explain the whole 10 percent increase. Second, these customers would still have bought gasoline from XT anyway, just in smaller and more frequent purchases. So C mostly concerns purchase pattern, not whether the promotion caused XT’s total August sales to rise.

(D) Did XT or any of its gasoline stations have to pay other businesses to provide the car washes that customers were offered in the promotion?

This is also about cost or profit, not whether gasoline sales were boosted.

(E) Are XT’s gasoline sales in August usually significantly higher than one twelfth of XT’s annual gasoline sales?

This does not compare last August with the previous August in a useful way. The argument is about whether the promotion caused a year-over-year August increase.

Answer: (A)

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25 Jun 2026, 23:40

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Hi GulfTube,

Your instinct to run the Yes/No test is exactly right, and you've already half-spotted the issue when you flagged the word "any." But the deeper reason (C) is out is something earlier in the choice - once you see it, "any" stops being the load-bearing word.

The phrase doing the damage isn't "any" - it's "in lower quantities, but more frequently"

Read that pair together. "Lower quantities, but more frequently" is the classic GMAT setup for same total, different pattern. The customer who used to buy 2 gallons on 5 visits is now buying 10 gallons on 1 visit - same 10 gallons either way, just bunched into fewer trips.

That's the assumption you yourself made in your post ("assuming that the amount of fuel... is the same"). The choice is built on that assumption.

Now re-run the Yes/No test with that locked in

- Yes - such customers exist. They bought 10 gallons during the promotion; without it they'd still have bought 10 gallons, just over more visits. Same revenue either way, so the promotion didn't move the needle for them, and it doesn't explain the 10% rise.
- No - no such customers exist. Then we just don't know anything about why the 10% rise happened. Doesn't explain it either.

Both answers leave the conclusion in the same place. That's the real disqualifier - and it's exactly what KarishmaB was pointing to upstream.

Where "any" fits in

You're not wrong about "any" - it's a secondary weakener (even one such customer wouldn't tell us about the rest of the base). But you don't need it. (C) is already dead from the quantity logic; "any" is just an extra nail.

A quick stand-in to lock it in

Swap one word and feel the difference. If (C) had said "...would have bought gasoline at the same station in lower total amounts", then Yes would genuinely weaken (these customers bought more gas because of the promotion). That single swap is what would make (C) live. As written, "lower quantities, but more frequently" closes that door.

Answer: A

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