Some private taxi drivers in Crimea equipped their cars with air condi

Narrowed the answer choices down to A and D, and went with D. Here's why:

Taxi Drivers
Some installed A/C units -> led to happy customers -> resulted in more tips >>>> Conclusion: ALL cabs get A/C = bigger tips for ALL cabs

Right off the bat a red flag goes off- just because some cabbies got received higher tips does not mean a mass installation of A/C units will result in more tips for everyone. Remember, correlation does not imply causation. As this is an assumption question, the following answer choices MUST be true for the conclusion to hold. Without that assumption, argument must fall apart. How will happy customers tipping more result in a scenario where if all cabs have A/C installed, everyone gets bigger tips?



Let's analyze the answer choices.

(A) Most passengers tipped better when they rode in a taxi equipped with air conditioning. This is wrong because it is not vital and necessary for the conclusion and does not entirely make sense. If this answer was in the passage it would read something like "if 95% of passengers tipped better in A/C equipped cabs, and all taxi drivers decided to install AC, they would all get larger tips." This is wrong because we do not know how the remaining 5% of passengers would tip - could tip more, could tip less. we do not know and therefore there is still some confusion. Answer choice is wrong.

(B) Customers do not generally tend to give bigger tips to drivers of large and spacious taxis than to drivers of smaller taxis. irrelevant argument as we are talking about A/C and not legroom of cabs.

(C) In the long term, the cost of installing an air conditioner will be more than offset by larger tips. irrelevant. The passage does not mention anything about installation costs. All we care about is tips.

(D)Customers will not take air conditioners for granted and revert to their usual tips if all Crimean taxi drivers equip their cars with air conditioners. Correct! This assumption must absolutely be 100% true for the conclusion to make sense. As the diagram above shows, Some AC= Happy customers tipping more = customers wont take AC for granted and go back to regular tips= if all cabs have AC, everyone gets more tip. This assumption is absolutely vital. Similarly, the negating of this answer choice absolutely devastates the argument. "Customers will take AC for granted and stop tipping more. Therefore if All taxi drivers get AC, everyone gets more tips" Negating kills the argument as it doesn't make sense.

(E) Some Crimean taxi drivers are reluctant to air condition their cars, even if it will increase their tips. Irrelevent. Being reluctant to install AC has nothing to do with generating more tips with the installation of AC. If anything this strengthens the argument.

Conclusion:
if all Crimean taxi drivers equip their cars with air conditioners, they will get larger tips than they do now.
Premise:
Some private taxi drivers in Crimea equipped their cars with air conditioners to make their customers more comfortable during the summer months. Tips received by those drivers from grateful customers were, on average, 5 percent higher than tips they received before they air-conditioned their cars.
Assumption: Making the AC a feature in all taxi's won't compromises the exclusivity of this service. If it is then customers would start taking this for granted and wont pay extra tips.

The argument above depends on which of the following assumptions?

(A) Most passengers tipped better when they rode in a taxi equipped with air conditioning.
[Negate this.Does it weakens the arg. Actually no bec arg is abt getting larger tips than they get now. Sort of trap]
(B) Customers do not generally tend to give bigger tips to drivers of large and spacious taxis than to drivers of smaller taxis. [how spacious taxis r not concern here.]
(C) In the long term, the cost of installing an air conditioner will be more than offset by larger tips.
[This is not a concern here.]
(D) Customers will not take air conditioners for granted and revert to their usual tips if all Crimean taxi drivers equip their cars with air conditioners.
(E) Some Crimean taxi drivers are reluctant to air condition their cars, even if it will increase their tips

ok, so PT with AC=> incr. 5% tips
concl: if all taxis install AC -> rcv better tips.

the assumption -> the trend will continue.

The argument above depends on which of the following assumptions?

(A) Most passengers tipped better when they rode in a taxi equipped with air conditioning.
well, let's negate this answer choice, most=51-100, so 51-100 passengers did not tip better, well, the other half - 0-50 tipped, so the conclusion is still valid. since it did not pass the negation test, it is not a correct answer.

(B) Customers do not generally tend to give bigger tips to drivers of large and spacious taxis than to drivers of smaller taxis.
well...spacious taxis compared with smaller taxis - out of scope.

(C) In the long term, the cost of installing an air conditioner will be more than offset by larger tips.
the argument is not concerned whether the drivers will cover the costs. thus, this is out of scope.

(D) Customers will not take air conditioners for granted and revert to their usual tips if all Crimean taxi drivers equip their cars with air conditioners.
aha, so if drivers take for granted that taxis must have AC, then they will not tip better, since it is no longer smth that rare to find, and the conclusion is shattered. negation test helped us here to ID that this is a correct assumption.

(E) Some Crimean taxi drivers are reluctant to air condition their cars, even if it will increase their tips
reluctant or not, installing AC can lead to increase of tips. so not a correct answer.

Premise: Grateful customers – 5% higher normal.
Conclusion: Equip air conditioners –ALL (100%) will get larger tips than now.
Choice B, C and E are out of cope.
Choice A, Most (1-99%) passengers tipped better when they rode in a taxi equipped with air conditioning. It means not all passengers will tip better, or even tip lower. It weaken the argument.
Choice D, Customers will not take air conditioners for granted and revert to their usual tips if all Crimean taxi drivers equip their cars with air conditioners. It means customers are aware that air conditioners are equipped for $, not for free, and customers not revert their usual tips. Both factors help us to know that they will tip more than now. Choice D correct.

A. It is the conclusion ,not an assumption
D.Assumption. Correct answer

Hello from the GMAT Club VerbalBot!

Thanks to another GMAT Club member, I have just discovered this valuable topic, yet it had no discussion for over a year. I am now bumping it up - doing my job. I think you may find it valuable (esp those replies with Kudos).

Want to see all other topics I dig out? Follow me (click follow button on profile). You will receive a summary of all topics I bump in your profile area as well as via email.
_________________