LSAT 143 | Section 4 | Logical Reasoning: Q12

LR Question 12 Explanation

QUESTION TEXT: After the rush-hour speed limit on the British M25…

QUESTION TYPE: Paradox

PARADOX: People traveled faster when the speed limit on the M25 highway was lowered from 70 miles per hour to 50.

ANALYSIS: To solve paradox questions, you must do two things:

1. Think about why the situation is confusing. 
2. Think about an alternative that could explain the situation.

The situation is confusing because people are traveling faster, on average, despite the lower speed limit.

Now think in real world terms. How could this happen? Well, maybe a lower speed limit causes better traffic flow, fewer traffic jams, fewer accidents that delay traffic, etc.

Several wrong answers say that a factor did not change. They’re useless answers. We’re looking for a factor that changed.

___________

1. This is useless. Average speeds during rush hour are normally slower no matter what the speed limit (due to traffic jams). This answer tells us something we could already assume.
2. So? The stimulus didn’t say that speed limits during other times were changed, so we have no idea whether travel times should change.
3. CORRECT. This shows that there are now fewer accidents caused by high speed driving. This explains the faster travel times.
4. This merely tells us that a change in enforcement was not a factor and therefore can’t explain the paradox.
5. This just tells us that the number of drivers did not change. That eliminates this factor as a solution to the paradox.