PrepTest 155

This diagrams as:

Jamil's Cat Outside → Temp Above Freezing

This doesn't match either of our anticipations. An experienced LSATer might eliminate this upon noticing that "Temp Above Freezing" is a necessary condition in this answer choice — recall that "Temp Above Freezing" is only a sufficient condition in the passage.

This diagrams as:

 Jamil's Cat NOT Outside → NOT Sunny & NOT Hot.

This answer choice negates the conditions in our original conclusion, but doesn't also reverse the conditions to form a valid contrapositive. This is not necessarily true (Jamil's cat could be indoors on a hot, sunny day, simply because the cat doesn't want to go outside), so this is incorrect.

Experienced LSATers might eliminate this one upon noticing that "Sunny" and "Hot" are sufficient conditions in this answer choice — recall that those conditions were only necessary in the passage. If you need to diagram this one to see why it's wrong, that is OK too! This one diagrams as:

Sunny or Hot -> Jamil's Cat Probably Outside

This one reverses the conditions in our original conclusion, but doesn't also negate them to form a valid contrapositive. Like (B), this is not necessarily true (Jamil's cat could be indoors on a hot, sunny day, simply because the cat doesn't want to go outside), so this is incorrect.

It's worth noting that the "probably" does not make this answer choice wrong. The passage uses strong language, which can support an answer choice that uses weaker language like "probably."

This one diagrams as:

Family Member Outside -> Jamil's Cat Outside

This simply reverses the conditions in the second premise, but without negating them to form a valid contrapositive. This is not necessarily true (even if Jamil's family members are outside, the cat could stay indoors simply because it doens't feel like going outdoors), so it is incorrect.

Argument or Facts:
Facts

Question Type:
Must Be True

Stimulus Summary:
If it's above freezing, most cats want to go outside. But Jamil's cat is only allowed outside if a family member is also outside. Jamil's family only goes outside if it's sunny or hot outside.

Strategy Overview:

1. Argument or facts in passage?
   1. If argument, identify premises and conclusions
2. Sufficient/necessary conditions in the passage?
   1. If so, diagram statements and draw any deductions
3. Use anticipation to find the answer choice that is absolutely 100% true

Answer Anticipation:
We'll need to diagram this one since it's got a lot of diagramming keywords like "when," "unless," and "only." Recall that "when" is a sufficient-indicator word, "unless" requires us to negate the sufficient condition, and "only" is a necessary-indicator word.

1. Temp Above Freezing → Most Cats Want to Go Out
2. Jamil's Cat Allowed to Go Outside → Family Member Outside
3. Family Member Outside → Hot or Sunny

We cannot do much with the first part since it doesn't share terms with any other part of the stimulus. But the second two statements share the transitive property of "Family Member Outside," so they can be combined to draw a conclusion:

Conclusion: Jamil's Cat Allowed to Go Outside → Hot or Sunny

And its contrapositive:

Contrapositive: NOT Hot & NOT Sunny → Jamil's Cat NOT Allowed to Go Outside

So we've got two potential correct answers in this valid conclusion and its contrapositive.

Answer Choice Explanation:
This gets closest to matching the contrapositive of the conclusion we drew above. We can diagram this one as:

NOT Sunny & NOT Hot -> Jamil's Cat NOT Outside.

Now, this answer choice isn't perfect. The contrapositive we drew was technically, "NOT Hot & NOT Sunny → Jamil's Cat NOT Allowed to Go Outside." Observant test-takers and/or cat owners might note that a cat that is not allowed to go outside might sneak out anyway. However, this is the only answer choice that doesn't reverse the conditions without negating them or negate the conditions without reversing them. Those are two cardinal sins on a diagrammable Must Be True questions, and answer choices that commit either are never correct on such questions. So, we are forced to pick the close-enough (E). Let this be a friendly reminder that these questions are written by fallible human beings, not omniscient logic deities.

Key Takeaway:
Don't forget your contrapositives. They're simple but crucial. Well-prepared test-takers get into the habit of taking the contrapositive of their deductions. This helps them recognize correct answers in the contrapositive form. These extra two seconds of diagramming could save you from a missed question!