LSAT 142 | Section 2 | Logical Reasoning: Q21

LR Question 21 Explanation

QUESTION TEXT: A government study indicates that raising speed…

QUESTION TYPE: Principle – Justify

CONCLUSION: We should raise the speed limit to the average speed level people drive at.

REASONING: Raising the speed limit will reduce the accident rate.

ANALYSIS: Principle: justify questions are deceptively simple. Often, the argument will be something like this: “We should do this thing, because it is beneficial”, and the right answer will be “we should do things that are beneficial”.

This seems obvious. Don’t we already know we should do beneficial things? No, we don’t. You can’t assume moral judgements on the LSAT. The right answer here will be along the lines of “we should do things that reduce the accident rate”?

That seems obvious. Why can’t we already assume that? Actually, there are plenty of reasons we might not want to raise the speed limit even if it reduces accidents:

• Higher speeds burn more fuel, killing people from air pollution.
• The reduction in the accident rate will be very small, and raising the speed limit will cost a lot of money.

The LSAT is training you to separate your beliefs about what “should” be true from your judgements about the facts. Merely seeing “ooh, a benefit!” doesn’t always justify taking an action: there are always tradeoffs in life.

___________

1. The conclusion was only talking about the speed limits for high speed roadways. This answer adds nothing. It doesn’t matter whether speed limits applying to non high-speed roadways are also uniform. 
2. This adds nothing. The conclusion already said that we should make a uniform national speed limit for high speed roadways. This answer only extends that idea to other highway laws, which are irrelevant.
3. This adds a necessary condition for making a uniform law. Necessary conditions never help you prove something. They only add another obstacle to proving something. Even if you meet the necessary condition, you’re no closer to the goal.
    
   Suppose I said that only people who own orange clothes can enter law school. That’s an easy condition to meet, but it doesn’t help anyone get to law school, even if they meet the condition. “Orange” adds an obstacle, but brings no benefit.
4. This suggests the old laws are bad laws. But this isn’t specific enough: it doesn’t say that the new proposed law should be adopted.
5. CORRECT. This proves the conclusion. The new law will reduce the accident rate. This answer therefore tells us to adopt that law. (Per what I wrote in the analysis section, this answer is telling us to ignore tradeoffs and always do anything that reduces the accident rate.)