adkikani wrote:
Hi
GMATNinja generis GMATNinjaTwoCan experts please comment on using negation technique of D/A?
Quote:
Although the school would receive financial benefits if it had soft drink vending machines in the cafeteria, we should not allow them. Allowing soft drink machines there would not be in our students' interest. If our students start drinking more soft drinks, they will be less healthy.
The argument depends on which of the following?
(A) If the soft drink vending machines were placed in the cafeteria, students would consume more soft drinks as a result.
(B) The amount of soft drinks that most students at the school currently drink is not detrimental to their health.
(C) Students are apt to be healthier if they do not drink soft drinks at all than if they just drink small amounts occasionally.
(D) Students will not simply bring soft drinks from home if the soft drink vending machines are not placed in the cafeteria.
(E) The school's primary concern should be to promote good health among its students.
The author concludes that "allowing soft drink machines in the school cafeteria would not be in the students' interest. Why not? Because if the students start drinking
more soft drinks, they will be less healthy.
In order for the argument to hold, we need to assume that students will drink MORE soft drinks if the machines are added. In other words, the argument tells us that student health is negatively affected by an increase in soft drink consumption. But we don't know whether adding the machines will actually
increase soft drink consumption.
This represents a gap in the logic. What if students will drink the same amount if the machines are installed? In that case, adding the machines would have no impact on the students' health, and the argument would fall apart.
Choice (A) eliminates this possibility and fills the gap. If we negate (A), then students might not drink more soft drinks when the machines are added. In that case, the argument is not valid.
As for choice (D), let's say that the students WILL bring soft drinks from home if the soft drink vending machines are not placed in the cafeteria. At first glance, this might seem to impact the argument. If the machines aren't there, the students will simply bring soft drinks from home.
But choice (D) doesn't tell us anything about the QUANTITY of soda that is consumed in each case. For example, without the machines, a student might bring one soft drink bottle from home every day. WITH the machines, that student might purchase TWO soft drink bottles every day. Adding the machines increases that student's soft drink consumption even though choice (D) is not true. Negating (D) does not necessarily affect the argument, so (D) should be eliminated.
(A) is the best answer.