Logical reasoning PrepTest 150 · Section 2 · Question 2

Correct. Argument or Facts:
Argument

Valid or Flawed:
Flawed

Question Type:
Strengthen with Necessary Premise

Stimulus Summary:
Humans killed off mammoths about 13,000 years ago. A fossil etched with the image of a mammoth was found in the remains of a settlement, so that settlement must have existed in the time of the mammoths.

Answer Anticipation:
There are three moving parts here: the timeline for the mammoths, the settlement, and the engraving. The argument tries to connect the settlement and engraving to the mammoth timeline, but it does so only by stating that a mammoth is depicted. This doesn't tie the engraving to the time of the mammoths, or the engraving to the settlement. The correct answer is going to have to connect that engraving and the settlement to the time of the mammoths. After all, something doesn't have to still exist for it to be depicted in art, and something can be placed in a settlement after it was no longer occupied.

Answer Explanation:
Right off the bat, an answer is presented that connects the timing of the settlement and the engraving. If the engraving wasn't created when the settlement was occupied, there's nothing tying that settlement to the time of the mammoths, and the whole argument falls apart.

Key Takeaway:
When time is mentioned on the LSAT, it frequently factors into the analysis of the logic. Make sure that any evidence presented lines up with or indicates the specific time.

Incorrect. It doesn't matter what the engraving was made on, since depicting a mammoth suggests the engraver was aware of mammoths. Additionally, had the engraving been on a mammoth bone, that would, if anything, help the argument, so this answer can't be necessary.

Incorrect. First, living examples of mammoths aren't necessary for someone to depict them in an engraving. Getting past that, this answer is still too extreme in saying since mammoths would disappear from all of North America, since they could just have disappeared from any area close enough for the engraver to have potentially seen one in their life.

Incorrect. Even if the engraving technique was used elsewhere, the presence of this engraving in the remains of the settlement could be evidence that it coexisted with mammoths. For example, if the engraving technique was also used in a remote part of Australia, that almost certainly wouldn't impact what's going on in North American 13,000 years ago.

Incorrect. Lacking alternative means of verification isn't necessary to reaching a conclusion. For example, 2 * 4 = 8, which you can learn by memorizing a multiplication table. To do so, you don't need to assume that you can't add 2 4 times.