Over the past five years, the amount of gasoline used for transportati

Over the past five years, the amount of gasoline used for transportation per person per year has decreased. Over the same period, the number of cars per person has remained constant. Therefore, either the fuel efficiency of cars has increased, or the average distance driven per person has decreased, or both.

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




Therefore, gasoline consumption has decreased because of usage of alternative fuels and not because of fuel efficiency of cars has increased, or the average distance driven per person has decreased.







IMO B

Isn't alternative to gasoline out of scope?

No, the author mentions this has occurred either because fuel efficiency has increased or the average distance driven per person has decreased or both. B rules out an alternative explanation, if we negate B - the argument falls apart.

Why option B ?

Why not Option C?

Moreover , I request full explanation to differentiate between option A , B and C.

I request explanations on how to eliminate A and C among A,B and C.

MartyMurray Can you please explain why is A not the right answer? In case there were gasoline powered buses used. Won't that weaken the conclusion because essentially average is coming down because more people use the same transport mechanism and it not like the fuel efficiency of a car has increased or the average distance driven per person has gone down

I was stuck between A and B and was not sure which one to proceed with

 

Here's (A):

A. There were no new gasoline powered buses purchased for use in public transportation.

There are a couple reasons why (A) is not a necessary assumption.

One is that "new gasoline-powered buses" is not the same as "more gasoline-powered buses." After all, new buses could be purchased while older buses could have been retired. In that case, purchasing of new buses would not result in an increase in the number of buses in use and thus would not indicate that there may be an alternative reason, an increase in buses in use, for the decrease in gasoine use.

At the same time, even more important for eliminating (A) is that the argument already mentions the possiblity that "the average distance driven per person has decreased." Of course, the reason adding buses would result in decreased gasoline use would be that people are taking buses more and driving less. Thus, an increase in the number of buses in use would be in line with the argument's conclusion.

Simply put, the argument concludes that people may be driving less, possibly because they are taking buses more, and thus it does not require the assumption that there are not more buses in use.

 

 

Marty has already explained this option. This is a ''so what''? option.

If you negate A: You can say: Okay, there was one new gasoline powered buse purchased, so what?

There can be 10 million cars and 1 new bus in that city, and that way argument still stands intact.

Read the question carefully. It says ''gasoline used for transportation per person per year has decreased.
This option says: amount of gasoline used per person per year. We are not concerned about the total amount of gasoline used/person.
We are concerned about ''gasoline used for transportation PER person PER year.

Asit1995

Marty has already explained this option. This is a ''so what''? option.

If you negate A: You can say: Okay, there was one new gasoline powered buse purchased, so what?

There can be 10 million cars and 1 new bus in that city, and that way argument still stands intact.

Read the question carefully. It says ''gasoline used for transportation per person per year has decreased.
This option says: amount of gasoline used per person per year. We are not concerned about the total amount of gasoline used/person.
We are concerned about ''gasoline used for transportation PER person PER year.­