LSAT 135 | Section 2 | Logical Reasoning: Q14

LR Question 14 Explanation

QUESTION TEXT: Early urban societies could not have been maintained without …

QUESTION TYPE: Most Strongly Supported

FACTS:

1. Early urban societies needed large-scale farming, because other ways to get food wouldn’t have been able to support such dense populations.
2. Large-scale farming required irrigation.
3. In early times, irrigation was not feasible far from rivers or lakes.

ANALYSIS: The stimulus is basically a bunch of conditionals:

• Urban society → Large-scale farming
• Large-scale farming → Irrigation
• Irrigation → Nearby rivers/lakes

You can put those together in a chain:

Urban society → Large-scale farming → Irrigation → Nearby rivers/lakes

And the contrapositive:

No Nearby rivers/lakes → no Irrigation → no Large-scale farming → no Urban society

That’s all you need. A lot of the wrong answers add facts the stimulus never gives us.

___________

1. The stimulus is only about urban societies. It says nothing about where most people lived. Many people could have lived in small rural communities far from rivers.
2. Too broad. The stimulus only discusses urban societies, not societies generally. Small, non-urban societies could survive by foraging.
3. CORRECT. This is exactly what the chain tells us. If you’re far from rivers/lakes, then you have no irrigation, therefore no large-scale farming, and so no urban society.
4. The stimulus actually suggests the opposite. It says large-scale farming requires irrigation. Being near a river makes irrigation possible but it doesn’t eliminate the need for it.
5. Nothing in the stimulus compares rural societies’ food sources. We know foraging can’t support urban population densities, but that doesn’t tell us what rural societies mainly relied on.