PrepTest 106

[lcid:3521] Prep Test 106 LSAT — Logical Reasoning — S2 Logical reasoning

Question prompt

John works five days Remaining source text redacted.
Why the credited answer is right

Credited answer: D

The notes below walk through why it fits the stem and how to eliminate the rest.

Argument or Facts

Argument

Valid or Flawed

Flawed

Question Type

Strengthen with Necessary Premise Questions

Stimulus Summary

~Vacation AND ~National holiday → John works 5 days 4 days - Insurance company Friday - Blacksmith Last week - ~National holiday AND ~Vacation Therefore - John worked at the insurance company Mon-Thurs

Answer Anticipation

As with all Strengthen with Necessary Premise questions, let’s start this one by looking at the conclusion, attempting to find new concepts that need to be connected to the premises. Here, we get some - specific days of the week. The premises discuss only one such day - Friday - but here we get a conclusion about Mon-Thurs. What’s used to back that up? Well, last week didn’t have a national holiday, and John wasn’t on vacation. That means, according to the opening line, that he worked 5 days that week. When that happens, it’s split up with 4 days at an insurance company, and Friday he worked as a blacksmith. So we can conclude that he worked 4 days last week at the insurance company, and Friday wasn’t one of those days. However, that doesn’t mean that he worked Mon-Thurs at the insurance company! He might work some weekend days there. Let’s find an answer choice establishing that he doesn’t work weekends.

Answer choices

  1. A
    John never takes a Remaining source text redacted.
    Why choice A is not credited
    The argument’s conclusion is about last week, and we know he didn’t take a vacation then, so this answer is out of scope.
  2. B
    Every day last week Remaining source text redacted.
    Why choice B is not credited
    The argument isn’t about how much John worked on Mon-Thurs, just that he worked those days, so this answer is out of scope. Maybe if this answer were about only Friday, establishing that he couldn’t have worked as a blacksmith and at the insurance company that day, then it’d be a necessary premise. But in applying to every day he worked, it’s too broad.
  3. C
    John does not take Remaining source text redacted.
    Why choice C is not credited
    Similar to (A), since the argument is about only last week, a week that didn’t feature a national holiday or a vacation, this answer is out of scope. It doesn’t matter what John does in other weeks.
  4. D
    Last week John worked Remaining source text redacted.
    Why choice D matches the stem
    This answer rules out the weekend days as serving as some of the 4 days that John worked. If he worked 5 days, took the weekend off, and worked as a blacksmith Fridayd, that leaves Mon-Thurs as the 4 days he could have worked at the insurance company. If he did work on one of the weekend days, then that would eat up one of his 4 days at the insurance company, and he couldn’t have worked there Mon-Thurs.
  5. E
    There were no days Remaining source text redacted.
    Why choice E is not credited
    If John spent Monday evening working as a blacksmith after a full day at the insurance company, the argument could still hold together. Similar to (B), this answer is too broad in applying to every day. We’d need to know only that John didn’t work at the insurance company on Friday when also working as a blacksmith for the argument to work.

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