LSAT 139 | Section 4 | Logical Reasoning: Q20

LR Question 20 Explanation

QUESTION TEXT: Unusually large and intense forest fires swept the…

QUESTION TYPE: Must Be True

FACTS:

1. There were many big tropical forest fires in 1997.
2. An unusually strong el Nino caused more drought that year.
3. Many scientists think air pollution caused global warming, which made el Nino stronger.

ANALYSIS: Pollution might have made the fires stronger, or it might not have. To clarify the scenario where it didn’t, let’s give the drought a strength from 1-100. A level 1  drought is a weak drought. Level 100 is a terrible drought that wrecks the forest.

Let’s say you need a drought level of 65 to make the forest susceptible to large fires.

Without pollution, El Nino causes a level 70 drought. With pollution, El Nino causes a level 75 drought. Either way, the drought is strong enough.

We can say, if the scientists are right, that pollution contributed to the strength of the drought.

We can’t really say it contributed much to the size and intensity of the fires. It could be that past a drought level of 65, drought isn’t really a big factor on the size and strength of forest fires, and other factors become more important.

___________

1. Not true. Air pollution might have made El Nino stronger. But the drought could still have been strong enough even without the air pollution.
2. It’s possible that even a normal El Nino would have caused enough drought to create large forest fires. See the examples above.
3. We don’t know much about El Nino. That year it caused drought. Maybe it has other effects in other years. Or maybe other factors could prevent fires in those years.
4. The scientists would think that pollution enhanced drought. But the drought might still have been strong without air pollution.
5. CORRECT. El Nino caused drought. So if El Nino were stronger, then it probably made the drought stronger.