Logical reasoning PrepTest 137 · Section 3 · Question 18

Incorrect. Since this argument reaches a conclusion that an activity is acceptable, we should look at the original rule. However, that rule speaks to activities that pose risks to life. Does this car pose a risk to life? And if so, does it just pose a risk to the salesperson's life, or does it pose a risk to his fellow motorists as well? Without knowing that, we can't say if the rule applies, or who has to voluntarily assume the risk, so we can't select this answer.

Incorrect. Since this argument reaches a conclusion that an activity is acceptable, we should look at the original rule. However, that rule speaks to activities that pose risks to life, and the risk here is noted as being minimal. Ignoring that, it's also unclear that those who are breathing in the smoke are doing so voluntarily or receiving a net benefit that can't be gained without assuming the risk, so this answer is unsupported.

Correct. Argument or Facts:
Facts

Question Type:
Principle (Must Be True)

Stimulus Summary:
Life-threatening activities acceptable ←→ Each person involved gains net benefit only attainable through risk OR Bears risk voluntarily

Answer Anticipation:
In Principle (Must Be True) questions, we want to line the principle (generally a conditional) up so that the judgment being made is the necessary condition. Here, the statement is a biconditional, so both statements are both sufficient and necessary, but let's flip this around from the form it's given because the most likely way the answers will be phrased is to conclude whether a risky activity is acceptable:

Each person involved gains net benefit only attainable through risk OR Bears risk voluntarily ←→ Life-threatening activities acceptable

And since the contrapositive will let us reach a conclusion that these activities aren't acceptable, we should take that to prepare (remember that in biconditionals, since the arrow points both ways, we can flip them, so a contrapositive can be taken just by negating both sides—we do that here to keep the conclusion about acceptability on the side that's normally necessary):

not Each person involved gains net benefit only attainable through risk AND not Bears risk voluntarily ←→ not Life-threatening activities acceptable

Since this principle is a biconditional, it can support arguments that reach a conclusion that a certain activity is acceptable, or that it isn't, so we're not going to be able to make quick eliminations based on that as we can in many of these questions, so it's going to be a bit of a slog. As always, when we know our answer analysis is going to take longer, we should head to the answers ASAP.

Answer Explanation:
Since this argument reaches a conclusion that an activity is acceptable, we need to look at the original rule. This situation does involve a risk to the motorists life, so the rule applies. There's no discussion of any net benefit, but it does establish that the motorcyclist is bearing this risk voluntarily, and not wearing a helmet only endangers the life of the motorcyclist. Since this scenario meets one of the individually sufficient conditions of the first rule, it justifies the conclusion that this risk is acceptable, so this answer is correct.

Key Takeaway:
Principle (Must Be True) questions ask you to apply a conditional to a situation. You generally want to get the judgment (here, that a risk is acceptable) into the necessary condition and work from there. Outside of diagramming the principle(s) in the stimulus and possible taking contrapositives, there's not much work to be done during the anticipation step, so spend your time making sure that the answer you select lines up with all the details from the principle—you may have dropped somewhen you wrote out your diagram, so confirm with the actual text before bubbling in your answer!

Incorrect. Since this argument reaches a conclusion that an activity is acceptable, we need to look at the original rule. However, while all motorists share in the benefit of inexpensive, convenient travel, pollution poses risks to non-motorists who don't receive that benefit. Since each person who bears the risk doesn't gain a benefit, the sufficient condition isn't met and we can't conclude that this risk is acceptable.

Incorrect. Since this argument reaches a conclusion that an activity is acceptable, we need to look at the original rule. However, it explicitly doesn't pose a risk to life, so that rule doesn't apply and we can't reach any conclusion about the acceptability of the risk.