M838TE wrote:
GMATNinjain general, if the argument statement provided did not specify a certain type of information, then we could not use the information in the answer choices as the basis of evaluation? in other words, I was thinking that what if the number of hours a worker put in is proportional to the waste produced and all else equal? same total worker but less hours per day and less total waste.
I recalled there was a post about common sense application in CR, and I thought this assumption I made may be in the grey area. I guess just gotta avoid grey answers and choose the best..
On many CR questions, you're looking for the "best" option out of the five answer choices. For example, if the question reads, "which of the following, if true,
most strengthens the argument?" or "Which of the following would be
most helpful in evaluating the argument?" or "Which of the following
best expresses the conclusion of the argument as a whole?"
Because these questions use words like "most" or "best," you're really just looking for the answer choice that is better than all of the other options.
That's not the case for this particular question. Here, we're asked to find which answer choice "
is an assumption on which the argument depends." So, we're not looking for the
most-assumption-y option, we're looking for the one option that fulfills a particular role. One of the answer choices MUST be true in order for the argument to hold, while the other ones don't necessarily have to be true in order for the argument to hold.
Before we dive into the answer choices, here's a look at the argument:
- The author gives us some background information: "an airplane manufacturer implemented a program with the well-publicized goal of reducing by half the total yearly amount of hazardous waste generated by its passenger-jet division."
- The author concludes that: "charges that the manufacturer's program has not met its goal are false."
- The author supports this conclusion with a fact: "When the program began in 1994, the division's hazardous waste output was 90 pounds per production worker; last year it was 40 pounds per production worker."
Overall, the author believes that the airplane manufacturer HAS met its goal. That goal was to reduce by half the hazardous waste from the passenger-jet division. The author's evidence for this belief is that the waste output
per worker declined from 90 pounds to 40 pounds.
Here, you can begin to see a gap in the argument: the author thinks that overall waste production must be down by 50% because waste production
per worker is down by over 50%.
So, which answer choice is an assumption on which the argument depends?
Quote:
(D) The average number of weekly hours per production worker in the passenger-jet division was not significantly greater last year than it was in 1994.
The evidence is given in
pounds of waste produced per worker. So, whether a worker works 1 hour each week or 40 hours each week, he/she still only counts as one worker in the equation.
Let's say that workers DO work a lot more hours now than they did in 1994. The author's argument is still fine -- perhaps this waste management program is amazingly effective, and even though workers are putting in a ton of extra hours and producing a bunch of planes, the overall waste is way down.
We have no way of assessing how each worker's hours impact the number of workers or the overall waste, which are the two factors at play in the argument.
Overall, (D) doesn't HAVE to be true in order for the argument to hold, so you can eliminate (D).
Quote:
(E) The number of production workers assigned to the passenger-jet division was not significantly less in 1994 than it was last year.
The author says that overall waste is down because waste per worker is down.
But wait a minute -- what if there are just
way more workers now than there used to be? Then overall waste could be exactly the same, even as waste per worker goes down. This completely destroys the author's argument, because it invalidates the evidence that he/she presented.
So, for the author's argument to hold any water, it MUST be true that the number of workers in 1994 was not significantly less than the number of workers now.
(E) must be true, so (E) is the assumption on which the argument depends.
I hope that helps!
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