In the nation of Partoria, large trucks currently account for 6 percen

Ans B

Why Not E: The argument is not talking about the maximum/minimum capabilities of trucks nor the loading capacities rather the argument is about the safety scenario regarding the usage of small/big trucks.

Option B says the assumed safety of largest trucks is not due to truck themselves rather depends upon the driver..!!

B it is.

the author says that if deaths have to be reduced in partoria then people should use more of triple trailer trucks (they are more safer).

Option B weakens the argument by pointing out that the triple trailer trucks are driven by the most experienced drivers. Hence, the deaths are less in case of triple trucks because they are driven by experienced derivers and not because the triple trucks are any special or safe.

Let's assume 1-T, 2-T and 3-T all travel equal number of miles and for the ease of calculation let's also assume that 1-T and 2-T were involved in 6 accidents/mile each.
Then,
accident rate (3-T) < (1/3)(1-T) = (1/3)*6 = 2; accident rate(3-T) < 2/mile
accident rate (3-T) < (1/3)(1-T) = (1/3)*6 = 2; accident rate(3-T) < 2/mile
Total accident rate (3-T) <4/mile. This is still less than the what it is for 1-T and 2-T
What am I missing over here?

Rule 1 - Please DO NOT ASSUME anything in question stem in CR

In this question, Large trucks are involved in 6% of miles driven
It is the average of (1T,2T,3T) large trucks...Nowhere in the question is it given the differentiation among 1T/2T/3T trucks the number of miles driven, so how can you assume they have driven the same miles?

Your Assumption was FALSE...You did not understand the question stem...That is what you were missing.

This question appeared as the first question Verbal section of my GMAT Prep Test 1 , and I got it wrong. Option B looked good to me but option E appealed more.
Can somebody, experts, please explain why option E is incorrect? If the payload of the largest trucks is less , doesn't it mean that they are less prone to accidents than smaller trucks which in addition to being small are carrying more loads?

To answer your question:
No. The text does not say anything like that, yours is an additional assumption.

We want to weaken that "one way for partoria to reduce highway deaths would be to reduce shippers to increase their use of triple trucks."

E talks about the maximum payload
E. In patoria, the maximum legal payload of a trailer truck is less than three times the maximum legal payload of the largest of the single trailer trucks.
that is nowhere mentioned in the passage, so we cannot infer that is connected somehow to the incidents.

B on the other hand says that
B. so far only the best, most experienced drivers for Patorian trucking companies have been driving triple trailer trucks.
so the data on which the conclusion is based ("The very largest trucks those with three trailers had less than a third of the accident rate of single and double trailer trucks.") is not reliable, so the whole argument is weakened.

Hope it's clear

@blueseas: I meant to say that option E gives one reason for the reduced accident rate for very large trucks like option B does.
@zarrolou: Weaken question always have information which is alien to stimulus like option B which talks about drivers but the stimulus provides us no information about the same.

In the nation of partoria, large trucks currently account for 6 percent of miles driven on partoria's roads but are involved in 12 percent of all highway fatalities. The verylargest trucks those with three trailers had less than a third of the accident rate of single and double trailer trucks. Clearly, therefore, one way for partoria to reduce highway deaths would be to reduce shippers to increase their use of triple trucks.

which of the following, if true, Most seriously weakensthe argument ?


B. so far only the best, most experienced drivers for Patorian trucking companies have been driving triple trailer trucks.:
this option tells us that drivers who drive the triple trailer truck...they are the best and the most experienced....and that is the reason accident rate with these type of truck is less and not because..these types of trucks are safe.

E. In patoria, the maximum legal payload of a trailer truck is less than three times the maximum legal payload of the largest of the single trailer trucks.
now in this option ...it is talking about the maximum payload....but how can we connect this payload thing with accident rate...it can also be possible that more the payload more the stable and easy to manoeuvre trailer is....but cannot directly relate to accident rate.
moreover...it says that maximum load it can take...it doesnt say IT ALWAYS HAS TO TAKE THAT MUCH LOAD...so in no way it weakens.

hope it helps

P : Accidents occur due to Large trucks ( All T1 , T2 and T3 )

P : T3 contributed to approximately 33% accidents , whereas T1 and T2 contributed 67% of the accidents.

C : Hence T3 must be favoured


The author doesn't take into consideration the expertise of the drivers while reaching the conclusion .

It is possible that when T3 drivers are used to drive the T1 and T2 trucks accidents might be reduced...

Thus expertise of the Drivers must be the point of consideration , coz trucks don't travel on their own they are driven by Humans...

Conclusion:
according to argument we could reduce the number of accidents by increasing the use of 3 trailer trucks and reducing the use 1 and 2 trailers truck .

If we could prove that we can reduce the number of accidents by method other than mentioned in the conclusion, Then that would be the answer choice.

Choice B correctly states that we can reduce the number of accidents by hiring experienced drivers for 1 and 2 trailers truck also

let us break the argument down -

Premise
Large trucks - 6% of the miles driven BUT 12% of fatalities. (Seems to imply that trucks are more dangerous than other types of vehicles).
three trailer trucks have 1/3rd fatality rate of other large trucks

Conclusion
Use triple trailer trucks --> Reduce accidents

We have been asked to weaken the conclusion, i.e. to point out that this proposal may not lead to the conclusion - Reduce accidents.

A - Incorrect.
The objective here is to reduce fatalities caused by other large trucks by replacing them with triple trailer trucks. Since those roads are anyways not accessible to other large trucks also, this point is irrelevant.
If the accident rates on other roads are reduced, that would lead us to the conclusion - Reduce accidents.

"some smaller roads off limits" - the word "some" is vague. What if only 0.1% of the roads are off limits? Then this issue has no statistical significance on the argument.

B - correct answer.
this weakens the conclusion by giving an Alternate Cause for the premise that -
triple trailer trucks are safe --> hence, 1//3rd accident rate

this gives us reason to believe that triple trailer trucks themselves may not be safe, but the lower fatality rate is due to better drivers.
If this is the case, we can say that using more of triple trailer trucks will NOT necessarily reduce fatalities on the road.

C - incorrect.
Still, this answer option does not change the fact that 12% of fatalities are from trucks. Those accidents may be between trucks and other vehicles then (since the truck to truck number is low)

D - Incorrect.
Does not mean that the conclusion -
"One way to reduce accidents is to use triple trailer trucks" is untrue.

E - Incorrect.
it should read "maximum legal payload of triple trailer trucks"

We have no idea how "legal payload" relates to "accident rates" or whether these limits are imposed or followed.
Hence, irrelevant.

VeritasKarishma please help with opt E... if payload (meaning carrying capacity) of 3 trailer truck is less than 1 or 2 trailer truck then ppl would require more 3 trailer trucks than 1 or 2 trailer truck to carry same weight and thus there would be more 3 trailer truck (increasing the overall accident rate)

From Option E, all we can deduce is that the largest trucks can carry more weight. There is no correlation between payload and accidents here. However option B gives us the correlation we are looking for.

Let's see if I can help you:

Let us consider the maximum payload capacity of single-trailer is 100 kg.
We will assume that the truck is always running in full load condition.
As per the statement the payload is less than three times the payload of single trailer. Let us consider the payload is 2 times - 200 kg.
Now lets say there are in total 12 single trailer trucks and 7 triples trailer. SIngle trailer reduces to 6 triple trailer trucks. Thus total triple trailer now are 13.

Accident rate single and double = say 15%
Accident rate of triple = less than third = 4%


A little vague calculation: previously accidents = (0.15* 12 + 0.04 *7) = 2.08

Current accidents = 0.04*13 = 0.52

Thus we can see that the accident rates have drastically decreased.

I know the calculations are not perfect and there are loads of assumptions. But I hope you get the idea!

I am so confused by the correct answer to this question. According to me, option B actually strengthens the argument. Since triple trailer trucks are driven by more experienced drivers, don't they automatically become safer than 1 or 2 trailer trucks?

lets just understand the information that we have

We are specifically talking about the nation Partoria. In Partoria, large trucks(number of the large trucks can be any number) currently account for 6% of the total miles driven on Partorian roads ie the number of miles driven by large trucks on partorian roads is 6% of total number of miles driven by all the vehicles, including cars, buses, etc etc.. (total number of miles driven by all vehicles can be any number)

Large trucks are "involved" in 12% of all highway deaths/fatalities. One thing to note here is that being involved in something doesn't mean causing that something.

The very largest trucks - those with three trailers - had less than a third of the accident rate of a single and double trailer trucks. Important thing to know here is the logical gap, which is the difference between accident rate and fatality rate. Accident rate is basically related to the number of accidents, and fatality rate is related to the number of deaths. So a low accident rate doesn't necessarily mean few fatalities or deaths.


conclusion : typical goal - plan structure ie

plan is : shippers must increase their use of triple trailer trucks

goal : reduce highway deaths


so basically we need to evaluate whether the mentioned plan which is "increasing the usage of triple trailer trucks" will help is achieving the goal, which is "reducing highway deaths".

now lets look at the options -


option A :

does this option help us in answering the question - whether the mentioned plan, which is "increasing the usage of triple trailer trucks", will help is achieving the goal, which is "reducing highway deaths" ? clearly not. Also this option is basically saying no matter what changes in regulation of trucking are made, large trucks, including both greater than or equal to three trailers and less than equal to two trailers, must be kept off small roads, roads that basically are not highways, but are conclusion is about the highways....Irrelevant : no impact


option C :

fatal collisions, collisions in which someone dies, can involve two cars, two buses, one car and one bus, two trucks etc etc..again, ask yourself whether this option helps us in answering the question - whether the mentioned plan which is "increasing the usage of triple trailer trucks" will help is achieving the goal, which is "reducing highway deaths" ? clearly not......Irrelevant : no impact


option D : okay so the safety record has improved slightly over the past 10 years, but that doesn't impact our argument, which is about the current situation in Partoria.... Irrelevant : no impact


option E : we have to understand that this option doesn't necessarily say that the triple trailer trucks are heavier than single trailer trucks. We can have a three trailer truck with each trailer with max payload of 50 kilograms making the over payload to 150 kilograms, and we can have a single trailer with max payload of 200 kilograms. Let us now consider that an average triple trailer truck is heavier than even a largest of a single trailer truck, maybe this is the reason that triple trailers have a lower accident rate than single and double trailers do as the triple trailers are heavier hence they move slower or whatever, but then we are concerned about the fatality rate ie number of deaths on highways. Heaviness can help us in explaining the accident rate, but how does it affect the number deaths, we can't really say...... this option is not relevant to our conclusion


option B : lets say that the partorian trucking companies have in total 100 truck drivers. Logically, best, most experienced will be a small percentage of the those 100 drivers, maybe 5 percent of the 100 drivers are best and most experienced. Obviously the best/most experience cannot be a large percentage of the total number of drivers right? So even if we increase the usage of triple trucks, then that won't help us in achieving our goal unless the number of best and most experienced drivers, which is a very small number, increases. The number of best, most experienced drivers will remain the same (give or take 1 - 2 drivers) even if they hire new drivers. So if the number/usage of triple trucks increases, not best and less experienced drivers will have to take on those new triple trailers and that could lead to a greater number of highway deaths.


PS : Hey experts, If you feel that my explanations are incorrect/incomplete/ not precise, please feel free to comment