A company sells rear-view mirrors and visors for a certain

Can someone explain why option C is incorrect

Premise: Because the company sells more rear-view mirrors than side-view mirrors
Conclusion: The company can increase sales by selling side –view mirrors and rear- view mirrors packaged together as one unit.

The assumption should help company increase sales.
Option "C" is too general. the product can refer to both mirror types.
Option "E" is correct.

I initially thought that C was the correct answer but realized that E was a better choice. The more I think about C, it seems like a weakener. The entire premise behind the company's plan to boost sales is that changing the way products have been sold can impact sales. If not, there's no point in packaging the rear-view mirrors and the side-mirrors as one item.

I would say "C" is too broad. The product has not been mentioned. Moreover "the sales of a product will not affect the sales" is a very general statement. We are not sure in what way it will not affect sales. In addition the focus is on the sales of rear view mirrors and "E" hits on that note. Hence "E" is a better assumption answer.

We can clearly boil the options to C and E.
Now Negation test comes into picture.
C: Sales of products WILL be affected by the way those are sold. = OK if it increases Conclusion stands, If it decreases conclusion falls apart. So this does not have an affective stand over whether we can assume it. So its WRONG.

E:Demand for rear–view mirrors WILL decline by as much as sales of side-view mirrors will increase: SO there won't be any profits the sales of one will decrease while one will increase by an EQUAL Amount. So NO INCREASE IN OVERALL SALES. Exactly what we need.

Correct answer must be E.

I also chose option C but now I realised the problem with it. Option C says sale will not be affected. If you apply ANT in this option then it will mean ‘Sale of the product will be affected’. Which could be in both ways. Sale can either increase or decrease. That’s why this option is wrong.

How can E be the right answer...it doesnt matter if the demand of one is increased or other is decreased..we have to buy a packaged deal anyway...

Posted from my mobile device

that's what I thought

A company sells rear-view mirrors and visors for a certain make of automobile. It also manufactures side view mirrors, but these aren’t as popular a product as are rear-view mirrors. Because the company sells more rear-view mirrors than side-view mirrors, the company can increase sales by selling side –view mirrors and rear- view mirrors packaged together as one unit.
The claim made above rests on which presupposition?

A. Visors do not sell as well as rear-view mirrors.
B. No other company sells rear-view mirrors separately.
C. Sales of a product will not be affected by changing the way it is sold
D. Mirrors should regularly be checked and replaced to maintain safety standards
E. Demand for rear–view mirrors will not decline by as much as sales of side-view mirrors will increase.

Conclusion: the company can increase sales by selling side –view mirrors and rear- view mirrors packaged together as one unit

Conclusion is TRUE, Option supporting the conclusion must be with in the Scope, Not generalized & TRUE

Option (A) --> Visors is out of scope
Option (B) --> Comparison with other companies is Out of scope (as we don't have any info on other companies)
Option (C) --> Sales of a product will not be affected by changing the way it is sold - True but a generalized statement
Option (D) --> Safety is out of Scope (actual interest is sales)
Option (E) --> Demand for rear–view mirrors will not decline by as much as sales of side-view mirrors will increase - TRUE, with in scope & statement aims at rear-view mirrors

Hence Option E

Understanding the argument - 
­A company sells rear-view mirrors and visors for a certain make of automobile. - Fact/Background info. 
It also manufactures side view mirrors, but these aren’t as popular a product as are rear-view mirrors. - Fact. 
Because the company sells more rear-view mirrors than side-view mirrors, the company can increase sales by selling side –view mirrors and rear- view mirrors packaged together as one unit. - Conclusion and supporting premise. Sales means overall sales. 

Option Elimionaiton - Assumption  

A. Visors do not sell as well as rear-view mirrors. - Out of scope. 
B. No other company sells rear-view mirrors separately. - "other company" is out of scope. 
C. Sales of a product will not be affected by changing the way it is sold - True for rear view but detrimental for side view. Distortion. 
D. Mirrors should regularly be checked and replaced to maintain safety standards - Out of scope. 
E. Demand for rear–view mirrors will not decline by as much as sales of side-view mirrors will increase. - Means overall decline. If we were earlier selling 100 rear views and 40 side views, so if we now sell 50 rear views, i.e., 50% decrease and now the side view is 50% increase, say 60 - so overall we become from 140 to 110. ok