Since City X passed a regulation requiring fast food restaurants to po

I have an doubt regarding option C. What if even after a decrease in the number of restaurants, the average price per restaurant goes up ? In such a case the revenue will not come down ! The reason why I say so is this - number of restaurants come down ; logically the existing ones will increase their price as demand will shoot up. Should not the revenue go up then ?

Please correct me !!

Since City X passed a regulation requiring fast food restaurants to post the caloric content of their food in prominent places, total revenue at the city’s fast food restaurants has decreased 10 percent. Clearly, City X’s regulation has encouraged people to eat healthier food.

Which of the following, if true, casts the most doubt on the conclusion drawn above?

A. The average price of meal at a fast food restaurant in City X has decreased by 5 percent.
Could be, but if so, why the decrease of revenue was 10%, probably because some people began t oeat healthier food ----> it is a strenghener, not a weakener

B. City X passed the regulation in response to a nation wide obesity epidemic.
Irelevant, fives us nothing

C. After the regulations were passed, a number of City X’s fast food restaurants closed down and moved their operations to locations outside the city.
Good. The fewer number of restaraunts ---> the less total revenue

D. The population of City X has remained unchanged since the passing of the regulation.
It is no an explanation

E. Surveys show that many citizens of City X do not approve of the new regulations.
Irelevant, fives us nothing

Source: McGraw-Hill's GMAT

Here only option C is giving another reason for lower sales. hence this option weakens the argument.

Hey spetznaz, good business logic! while you make a god point, it's not enough to cast serious doubt on C.
Why?
Well, take into account that we are not looking that proves for sure that revenues will go down for another reason, just for something that casts doubt on the reason given - that is, something that makes it likely that something else is the cause.
So, why is this answer likely despite the point you make? well, while it's very likely that the individual revenue of the specific restaurants that stay open will increase (as you point out), the chance that the overall revenue is very small indeed - it would require a huge - and unlikely - rise in the revenue of the specific restaurants.

Hi, I particularly need clarification about this: 'total revenue at the city's fastfood restaurants'. Does this mean total revenue per restaurant or total revenue of all restaurants. I'm quite confused about this because if it means the former, then those restaurants that left town won't really matter and if it means the latter then the OA is valid. So please help me understand.

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Premise : Since City X passed a regulation requiring fast food restaurants to post the caloric content of their food in prominent places, total revenue at the city’s fast food restaurants has decreased 10 percent.
Conclusion : Clearly, City X’s regulation has encouraged people to eat healthier food.

A. The average price of meal at a fast food restaurant in City X has decreased by 5 percent.
Average price decrease of 5% at a single fast food restaurant can't make a decrease of 10% revenue of total revenue of all fast food restaurant at city. (it is possible only if sale is very high for this particular restaurant.) Also decrease in price might attract more customers which may result in increase in revenue.
Let's keep it, it may weaken the statement.

B. City X passed the regulation in response to a nation wide obesity epidemic.
This is a cause of passing regulation but it doesn't weaken the statement.

C. After the regulations were passed, a number of City X’s fast food restaurants closed down and moved their operations to locations outside the city.
Correct
A number of City X's fast food restaurants closed down and moved outside the city. So, this caused the decrease in revenue overall directly. And hence this weaken the conclusion that the regulation has encouraged people to eat healthier food.


D. The population of City X has remained unchanged since the passing of the regulation.
Doesn't signify anything. Doesn't weaken the conclusion in any way

E. Surveys show that many citizens of City X do not approve of the new regulations.
Out of scope. This might have led to no decrease in revenue.

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