LSAT 3 | Section 2 | Logical Reasoning: Q12

LR Question 12 Explanation

QUESTION TEXT: Photovoltaic power plants produce electricity from sunlight…

QUESTION TYPE: Sufficient Assumption

CONCLUSION: Photovoltaic power plants are cheaper than traditional power plants.

REASONING: The cost of photovoltaic power has fallen to one tenth of what it once was while the cost of traditional power has increased.

ANALYSIS: If photovoltaic power used to cost $1000 per unit and traditional power cost 5$, this is a bad argument. Photovoltaic power would still be much more expensive.

We must show that photovoltaic power has actually become cheaper.

___________

1. The stimulus already tells us that the cost of traditional power has increased.
2. We’re concerned with the cost of electricity, not the quantity produced.
3. This doesn’t prove our argument correct. Photovoltaic power may still be more expensive.
4. CORRECT. If this is true, then photovoltaic power has become cheaper. You can prove it correct with a numerical example. Suppose photovoltaic used to cost $99 per unit of power, and traditional power cost $10. Now photovoltaic would cost 9.90$, and traditional power would cost more than $10.
5. We’re talking about the price of power now and not in the future.

Recap: The question begins with “Photovoltaic power plants produce electricity from sunlight”. It is a Sufficient Assumption question. Learn more about LSAT Sufficient questions in our guide to LSAT Logical Reasoning question types.