Auditor: XYZ, a construction company, purchased

Auditor: XYZ, a construction company, purchased 20 new trucks 3 years ago, and there is no record of any of those trucks being sold last year. Records indicate, however, that XYZ sold off all of its diesel-powered trucks last year. We can thus conclude that none of the 20 trucks purchased 3 years ago were diesel powered.

No record of those trucks were sold last year —> none of them were diesel powered.
(Those sold last year = diesel)

Leap: Just because they were not sold last year does NOT indicate that non of them were not sold at any time before that. So it is possible that some of the new trucks which are diesel-powered were sold 2 years ago. This must not be true otherwise the conclusion will break down.


Which one of the following is an assumption required by the auditor's reasoning?


We know this. Why tell us again? (A) is out.

Does this imply those new trucks are not diesel-powered? (B) is out.

Trucks other than those 20 trucks 3 years ago are irrelevant.

So this eliminates the possibility that the 20 truck were sold 2 years ago. Hang on to this.
[quote]v(E) XYZ no longer owns any trucks that it purchased more than 3 years ago.[/quo
te]
You don't own any more trucks. So you sold them all. Perhaps you sold them 2 years ago because they were diesel-powered that you don't like anymore. This matches our thought that weakens the argument. (E) is out.

Only (D) is left. D is our correct answer.

Struggling with this one for some reason.
Please help.

Let us break the stimulus down into premises and conclusion:

Conclusion: None of the 20 trucks purchased 3 years ago were diesel powered.

Premises (reasons/facts supporting the conclusion):

i) XYZ purchased 20 new trucks 3 years ago.
ii) There is no record of any of those trucks being sold last year.
iii) XYZ sold off all of its diesel-powered trucks last year.

We can see a clear gap in the reasoning. All of XYZ's diesel powered trucks were sold off last year and there is no record of any of the 20 new trucks that were purchased 3 years ago being sold last year. However, the conclusion is about all the trucks not being diesel powered. Clearly, in order to draw this conclusion, we need to know if any of the 20 trucks were sold in the years preceding last year as well, and whether any diesel powered trucks were sold in that period.

Let us analyze the options:

(A) All of the trucks that XYZ sold last year were diesel powered. This does not tell us anything about the period before last year and hence does not help in the conclusion. Eliminate.

(B) XYZ did not purchase any used trucks 3 years ago. There is nothing about used trucks in the stimulus. Irrelevant. Eliminate.

(C) XYZ did not purchase any new trucks since it purchased the 20 trucks 3 years ago. This does not tell us anything about what happened to the trucks after purchase and hence does not help in the conclusion. Eliminate.

(D) None of the 20 trucks was sold before last year. Correct answer. If none of the 20 trucks was sold before last year, none was sold last year either and XYZ sold all of its diesel powered trucks last year, then none of the 20 trucks were diesel powered.

(E) XYZ no longer owns any trucks that it purchased more than 3 years ago. Same as (C). Eliminate.

Hope this helps.

akela / mysterymanrog
Typo in (E), it should be "more" not "n1ore"

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Fixed that. Thank you!